As a rule, when carrying out repairs, a person spends a lot of physical effort. However, along with physical labor, mental labor is also actively used. For example, you need to do calculations. They are necessary so that the exact amount of building material can be calculated. A small amount of material contributes to disruption of the work schedule, but an excessively large amount makes repairs quite expensive. The calculations include calculation of area and perimeter (walls, ceiling and floor are measured). It’s worth talking in more detail about how to find the perimeter.

The simplest calculations are made in a room shaped like a rectangle or square: To carry out this operation, you will need primitive school knowledge. In the case of rooms that have the shape of a polygon, trapezoid and other complex shapes, the situation is much more complicated.

Feasibility of carrying out calculations

Most often, calculations are necessary when installing a plasterboard ceiling. To do this, you need to purchase several types of materials. If you do not make calculations, then there is a huge risk of making a mistake (even those who have extensive experience in creating such structures make mistakes). For example, often when determining the perimeter “by eye”, there is often not enough material.

In order to find out the total length of the wall profile, it is necessary to sum up all the lengths of the walls that form the room. This is often used to create sheathing.

You should purchase slightly more material (the acceptable rate is 10-15%). If there is a drawing or sketch, then the material must be purchased without excess.

Installing a stretch ceiling also requires calculations. This will allow you to most accurately take into account upcoming expenses.

The perimeter of the room is in the shape of a rectangle (relatively speaking, the length of the room is 5 meters, and the width is 2.5 meters), calculated using the following formula: P = 2 x 5 + 2 x 2.5 = 10 + 5 = 15.

The area of a room (for example, the length of its walls is 5 meters), which is shaped like a square, is measured using the following formula: P = 4 (number of walls) x 5 (length of one wall) = 20 meters.

The perimeter of a room with a rectangular shape and a square shape is quite easy to calculate. However, the perimeter of a room having a more complex shape is quite difficult to find.

How to calculate the area of a room with niches and projections

In order to find out the area of such a room, you need to measure the walls of this room. Niches and projections are divided into sections, and then their total length is determined.

How to calculate the area of a room with oblique corners?

Rooms can be built according to the same principle as in the case of niches and ledges. Take a tape measure and measure the length of all the walls of the room.

Oval or round room: how to determine the area?

To determine the perimeter of such a room, it is important to remember the school geometry course. The formula to find out the perimeter of a circle is as follows:

In this formula, P is taken to be the perimeter of the room, π is the number pi, which has a static value of 3.14 per and R is the radius. The radius is determined by measuring the diameter of the area extending between two walls located opposite each other.

P = π x (a + b).

In this formula, a, b are the semi-axes of the ellipse. In other words, in order to find out the area of an oval room, it is important to calculate the shortest and longest radii (they are the distance from the center to the edge).

Knowing the formulas clearly, complex figures are not a big problem. It is important to count accurately and correctly and be able to take measurements correctly.

Conclusion

As practice shows, finding out the answer to the question “how to calculate the perimeter” of a room shaped like a rectangle or square is not difficult. Premises with complex shapes require more complex and accurate calculations.

We have to count not only the “main” sides, but also various kinds of niches and recesses. With rooms that are made in the shape of an oval or circle, you have to consider the radius and diameter. For successful calculations, it is important to take correct measurements and be able to count correctly. If the calculations are made incorrectly, 10-15 percent of pre-stocked material will come in handy.

During renovation, a situation may arise when it is necessary to know the exact perimeter of the room, for example, when purchasing skirting boards or when calculating the amount of wallpaper and flooring. This is easy to do if the room has a standard shape. But what if we need to make calculations for a corridor that has many corners, or for a bedroom of an unusual shape? Some tricks that you can use to help with this process will help.

Calculation for standard rooms: square and rectangle

Most often there are rooms whose walls form a rectangle or square. In this case we will need:

roulette;
ruler;
thread;
paper and pencil.

First, let's remember what a perimeter is. This is a geometric quantity that is the sum of the lengths of all sides of the figure. Calculating it is even easier than.

The simplest case is a room that is a square, that is, all its sides are equal. Then we measure one side of the square by placing the tape measure at the junction of the wall and the floor.

If you don't have a tape measure, use a string to make a length that corresponds to the distance from corner to corner of the room and measure it with a ruler.

Calculation for standard rooms: square and rectangle

Most often there are rooms whose walls form a rectangle or square. In this case we will need:

First, let's remember what a perimeter is. This is a geometric quantity that is the sum of the lengths of all sides of the figure. Calculating it is even easier than the floor area.

The simplest case is a room that is a square, that is, all its sides are equal. Then we measure one side of the square by placing the tape measure at the junction of the wall and the floor.

If you don't have a tape measure, use a string to make a length that corresponds to the distance from corner to corner of the room and measure it with a ruler.

It's a little more interesting when the room is a rectangle. This means that the lengths of opposite walls are equal to each other. In this case, we measure the distance from corner to corner of two adjacent walls with a tape measure, add the resulting numbers together and multiply by 2. For clarity, consider an example: given a rectangular living room, the length of one wall is 5 meters, the other is 5.5 m. Then the perimeter will be equal to:

(5 + 5.5) x 2 = 21 (m)

Do not forget that even if you accurately calculate the amount of building materials, you need to buy them with a small reserve in case of damage.

Non-standard options: polygon and circle

It is easy to calculate the perimeter when the opposite sides of the figure are equal to each other. Let's complicate the situation: the existing kitchen has more than four corners. In this case, you will have to measure each segment from one corner to the other, and then add up all the measurement results. This method differs from the previous one in that in order to calculate the perimeter, more initial data is needed.

Let's take a kitchen that has the shape of a hexagon with a niche. Then the number of walls that we will have to measure by adding the resulting values will be equal to 8.

Let's complicate the situation even more: the hall is a circle. Measuring from corner to corner will not help here, since they simply do not exist. If you are sure that this is really a circle and not an ellipse, then knowledge of geometry will help. The perimeter represents the circumference of a circle. And the circumference, in turn, is the product of the diameter of the circle and the number π.

It sounds scary, but it's actually simple.

Find the center of the room and mark it.
We fasten the thread to one wall and draw it to the opposite wall through the center of the room.
We measure the length of the resulting segment. This is the diameter of the circle.

Now we need to count. We take the resulting diameter and multiply it by the number π. Everyone knows that this number is infinitely large. But we don’t need accuracy down to hundredths of a millimeter, so we take 3.14. Thus, the perimeter of the circle is the length of the line segment from wall to wall through the middle of the room, multiplied by 3.14.

This means that having a round room with a diameter of 5 meters, we will get the value we need as follows:

Borrow a laser tape measure from a friend. With this device, you will be able to take all the measurements yourself, unlike a tape measure, which requires a friend to hold its end. In addition, the device will give a more accurate result, since the laser beam will not be deflected. This will help you more accurately calculate the perimeter of the room.
Use a long thread. It will be much more convenient to attach parts of the thread to the corners without interrupting the measurement. The thread should unwind until it meets its own end - the beginning of the measurement. Its final length is the desired value. This method will help if you have a room shaped like an ellipse, since calculating the length of this figure in a different way will be problematic.

Thus, in a short time you can carry out all the necessary measurements and get the finished result. However, it is worth remembering that as a result, you need to take into account the error so as not to purchase less building material than you need. For example, if the wall is uneven, even with accurate calculations, you will end up needing more plinth to smooth out the imperfections.

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Repair is an activity that requires not only the completion of physical tasks, but very often, in order to properly build a space, you also have to engage in mental work - making calculations. They are mainly needed to ensure that the procurement of materials is accurate. After all, it’s not only unpleasant when the material runs out at the wrong time, but it also disrupts the work schedule. An excessive amount of material, on the contrary, can make the event excessively costly.

Therefore, a very often urgent task is to calculate the area and perimeter of a room: walls, floor, ceiling. Let’s talk about calculating the perimeter in more detail.

Making calculations in a small rectangular room is a fairly simple task. To do this, it was enough to study at least somehow at school. But the situation is much more complicated with those rooms that are made in the form of more complex shapes: for example, trapezoids, polygons and others.

Read more about why calculations are needed

We covered a little the topic of why such calculations are used. Most often they are relevant when creating a plasterboard structure on the ceiling. After all, this requires purchasing several different materials. And it is very difficult to do this without calculations, even with some experience in this area. If you estimate incorrectly, you may miss some necessary elements when building a structure.

So, to determine the total length of the wall profile, you will need to sum up the lengths of the walls of the room. This profile is used to construct the sheathing.

It should be remembered that for high-quality and prompt repairs, the purchase of material is carried out with some reserve - mainly 10-15 percent. Exceptional situations are those when there is an exact drawing or at least a sketch according to which the structure will be installed.

You will also need a calculation when ordering or installing a stretch ceiling, so that you can plan costs.

Calculation of the perimeter may also be required when determining the number of ceiling plinths, for example. Having found out the size of the perimeter, you need to divide it by the length of one plinth to determine the required quantity. And then add another 10-15 percent to this number.

For example, we have a rectangular room 5 meters long and 2.5 meters wide. The perimeter can be calculated using the following formula:

P = 2 x 5 + 2 x 2.5 = 10 + 5 = 15 meters.

It should be noted that with a square-shaped room, the formula is simplified. To calculate, you need to multiply one of the dimensions by 4. That is, if the length or width (and they are the same for such a room), say, 5 meters, the perimeter is calculated as follows:

P = 4 x 5 = 20 meters.

So, we have considered the option of a square and rectangular room, but what about more complex shapes? After all, then the calculations will be more complex.

Room with ledges and niches

Let's figure out how to calculate the perimeter of a space in which there are protrusions or niches.

So, the task ahead is somewhat more difficult than the previous one. We take measurements of all walls. On those walls where there are ledges or niches, you can divide the length into sections, summing them up.

Room with slanting walls

If the room has walls with oblique angles, the calculation is performed approximately according to the same principle. You need to take a tape measure and take measurements of the length of all the walls.

Oval or round room

Yes, in practice there are such rooms, although rarely. And then you can get into a stupor, stubbornly remembering the school course on how to calculate the circumference. And the formula looks like this:

P = 2 x n x r,

where P is the perimeter of the room, n is pi equal to 3.14, r is the radius of the circle.

This is how we calculated the circumference - if the room has a round shape. If the room is oval, then you will have to use ellipse calculations.

The formula looks like this:

P = n x (a + b),

where P is the perimeter of the room, n is pi equal to 3.14, a, b are the semi-axes of the ellipse. That is, this is the shortest radius and the longest - the distance from the center of the figure to the edge.

As you can see, there is nothing complicated even in calculations with such complex figures. The main thing is to take the correct measurements.

Probably, the question may arise, how to determine the center of the ellipse? To do this, you need to determine its axes - long and short. The point of their intersection will be the very center. At the same time, it will divide the axes into radii - semi-axes.

Calculation does not mean long and grueling measurements

To make all the necessary calculations during repairs, in particular to determine the area or perimeter of the room, you do not need to resort to special devices or complex calculations. It is enough to turn on logic and memory, remembering the geometry course from school. And if nothing comes to mind, then you can simply use our tips, which are presented in an accessible, understandable form for everyone.

It is important not to complicate the calculation procedure, then the event will not take much time and will be completed accurately. This means that the amount of material will be purchased exactly. And if there is any inaccuracy, it will be compensated by the reserve that is accepted when purchasing material - 10-15 percent more.

Often, when carrying out some repair work, people encounter certain difficulties if they need to make a calculation perimeter rooms. Believe me, for this you ideally do not need to have extensive knowledge in the field of geometry and algebra; just remember the school mathematics course.

You will need

– roulette;
– pencil and paper;
- a thread.

Instructions

1. Remember that the perimeter is nothing more than the sum of the lengths of all sides of some geometric figure. And it’s amazing when the room in which the calculations should be made has a standard shape, say, a square or rectangle. In this case, it’s enough to remember the school curriculum. For example, if the room is square, then to calculate it perimeter measure the length of one side and multiply the resulting total by four. The final number will be the perimeter of your rooms .

2. Find the lengths of 2 adjacent walls and multiply the sum of these numbers by two if the room is rectangular. The result is the perimeter of this room.

3. Measure all open segments and summarize the results obtained, if the room has some other arbitrary shape, which is quite common today.

4. Sometimes it happens that the room has the shape of a circle. If you are sure that the room is round, then measure its diameter, that is, the distance from one point of the circle to another, passing through the center. And after that, use the formula in which the perimeter will be nothing more than the diameter of the circle multiplied by a continuous value of 3.14.

5. All of the above methods are positive. But here’s the challenge: the premises do not always meet every technical requirement and standard, but it happens that the length of one wall differs from the length of the opposite wall. For such cases, we have an ideally easy and effective calculation method in our arsenal. perimeter rooms .

6. Take a regular thread as long as possible and lay it along each line perimeter. The place where it closes with the beginning of the countdown needs to be marked. And then measure the resulting length. The output of this measurement will be the perimeter of your rooms .

A circle is a geometric figure located on a plane. A circle consists of many points that are located at equal distances from a given center. In order to count it length, you can apply several formulas.

You will need

The following values will be needed:
R – length of the circle radius;
D is the length of the circle diameter;
? – constant (? = 3.14)

Instructions

1. Method 1. Let there be a circle on the plane. Its radius is R. Then length L this circle is calculated this way:L = 2?R.Example: Radius circle R = 5 cm. Then the length circle L = 2*3.14*5 = 31.4 cm.

2. Method 2. Let a circle with diameter D be given. Then L can be found like this: L = ?D. Example: Diameter circle D = 10 cm. Then L is calculated as follows: L = 3.14*10=31.4 cm.

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Note!
The results in the first and second methods are equal, since the length of the radius is equal to half the length of the diameter of the circle.

Many young parents would really like to influence the gender of their child. However, modern science has not yet learned how to program the gender of the unborn child. Sometimes it can be quite difficult to even determine who will be born. Probably, many of your friends have encountered incorrect determination of the baby’s gender during an ultrasound examination. Thus, it is quite difficult to calculate the sex of the baby, however, some validity was still noticed. For example, the theory of determining the sex of a baby by the blood of the parents is very famous.

You will need

In order to calculate what gender your future child will be, it is advisable to know the exact date of his conception, and also have a piece of paper and a pen with you.

Instructions

1. Divide a sheet of paper into two columns, at the beginning of each of which write the parents' birth dates.

2. It is believed that the blood in the male body is completely renewed in 4 years. Thus, add 4 years in the column of your husband’s age until you reach a particularly close date to the time of conception of the child. The blood in the female body circulates much faster, therefore it is completely renewed every 3 years. Based on this, in the column where the age of the expectant mother is indicated, the initial date must be increased for each person by 3 years, again until she is as close as possible to the moment of conception.

3. Now compare the data in both columns. If the mother’s blood is “older” than the father’s blood at the time of conception, then most likely you are expecting a girl. If on the contrary, then you need to tune in to the boy.

Note!
If you or your husband were donors or experienced a major operation associated with blood loss or transfusion, then it is necessary to count the periods of blood renewal precisely from the date of these events.

Helpful advice
It is also possible to determine the gender of the unborn child using ancient Chinese tables. Many women trust them unconditionally. You can find a presentation of the tables, as well as the rules for their use, on any forum dedicated to pregnancy planning.

Perimeter is the total length of the sides of the geometric figure. But if the need arises to quickly calculate the perimeter of something (say, during repairs or construction), not everyone will be able to do this with ease. Let us recall the basic rules for calculating the perimeter.

You will need

geometric figure, ruler, pen

Instructions

1. Perimeter for squares and rhombuses is calculated using the formula P = 4a, where a is the length of one side of the figure. Since all its sides are equal, measure one side and multiply the resulting number by the number of sides, i.e. by four.

2. For rectangles and parallelograms, because not all sides are equal, but only opposite ones; there is another formula: P = 2 (a + b). By a and b we mean adjacent sides. Multiply their total length by two.

3. To get the perimeter of a trapezoid, sum the lengths of all its sides (for a trapezoid they are not identical), i.e. in this case, use the formula P=a+b+c+d.

4. The general formula for calculating the perimeter of a triangle looks like P = a + b + c, i.e. you will have to add up the lengths of the sides of the triangle. But due to the fact that triangles come in different types, calculations can be done the other way around. Say, if you know that the triangle you are measuring is equilateral, then multiply the length of its side by three.

5. It is more difficult to calculate the perimeter of a circle (circumference, p). It is known that the circumference is 317 times the diameter of the circle (d). IN mathematics This ratio is usually denoted by the letter “Pi” (?) and is averaged as 3.14. It turns out that рd=?. Hence p=?d=2?r, where r is the radius of the existing circle. Consequently, in order to calculate the perimeter of a circle, you first need to find the radius of the circle, and then multiply this number by 2 and by 3.14.

6. If you need to find out the perimeter of the arc, then first you need to measure two quantities - the length of the arc radius and the central one, i.e. formed by two radii (in degrees, n). Substitute the obtained values into the formula p=Prn180°.

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When purchasing round timber for construction, it becomes necessary to calculate it. Finally, timber industry enterprises provide settlement services, but the settlement is carried out by employees of the same timber industry enterprises, which constantly leads to disagreements in calculations.

Instructions

1. In order to calculate the cubic capacity of round timber, it is possible to use special tables - cubic meters of the standard ISO 4480-83 and GOST 2708-75. You just need to measure the diameter of the upper end of the log and its length, and then use the tables provided to determine its cubic capacity. By adding up the cubic capacity of all the logs step by step, you will find the total cubic capacity of the round timber you purchased.

2. There are a lot of calculation programs on the Internet in which you can calculate the cubic capacity of round timber without using a table, but only by measuring the diameter and length of the logs. Tables have already been included in the programs. However, this is not always comfortable.

3. There is another method for measuring the cubic capacity of round timber - recalculating a folded cubic meter into a dense cubic meter. This is necessary because retail prices are usually set for dense cubic capacity.

4. Sort the business slab into two groups by length: up to 2 m in length and longer than 2 m. Place the slab in a stack, alternating thick and thin ends in opposite directions.

5. It is allowed to lay a short slab with a joint along the length. Make sure that the stack has an identical height along each length, is stacked as tightly as possible and has even right angles.

6. Multiply the average stack length by its height and width. The resulting figure will be the folded cubic capacity of round timber.

7. Multiply the figure of the folded cubic capacity by the corresponding indicator in order to obtain the mass of dense cubic capacity: the indicator for an unbarked slab up to 2 m is 0.48, for a length greater than 2 m – 0.43; the indicator for debarked croaker up to 2 m is 0.56, for a length greater than 2 m – 0.50.

8. Finally, you can entrust the calculation of cubic capacity to warehouse workers, but it still doesn’t hurt to check the accuracy of the calculations. It's in your best interest.

Perimeter(P) is the sum of the lengths of all sides of the figure, and a quadrilateral has four of them. This means that in order to find the perimeter of a quadrilateral, it is necessary to easily add the lengths of all its sides. But we know such figures as a rectangle, square, rhombus, that is, positive quadrilaterals. Their perimeters are determined by special methods.

Instructions

1. If this figure is a rectangle (or parallelogram) ABCD, then it has the following properties: parallel sides are equal in pairs (see figure). AB = SD and AC = VD. Knowing this ratio of the sides in this figure, it is possible to derive the perimeter rectangle(and parallelogram): P = AB + SD + AC + VD. Let some sides be equal to the number a, others to the number b, then P = a + a + b + b = 2*a = 2* b = 2*(a + b). Example 1. In a rectangle ABCD, the sides are equal to AB = CD = 7 cm and AC = WD = 3 cm. Find the perimeter of such a rectangle. Solution: P = 2*(a + b). P = 2*(7 +3) = 20 cm.

2. When solving problems involving the sum of the lengths of the sides with a figure called a square or rhombus, you should use a slightly modified perimeter formula. A square and a rhombus are shapes that have identical four sides. Based on the definition of the perimeter, P = AB + SD + AC + VD and allowing the length to be designated by the letter a, then P = a + a + a + a = 4*a. Example 2. A rhombus has a side length of 2 cm. Find its perimeter. Solution: 4*2 cm = 8 cm.

3. If a given quadrilateral is a trapezoid, then in this case it is primitive to add the lengths of its four sides. P = AB + SD + AC + VD. Example 3. Find the perimeter of the trapezoid ABCD if its sides are equal: AB = 1 cm, CD = 3 cm, AC = 4 cm, VD = 2 cm. Solution: P = AB + CD + AC + VD = 1 cm + 3 cm + 4 cm + 2 cm = 10 cm. It may happen that the trapezoid turns out to be isosceles (its two sides are equal), then its perimeter can be reduced to the formula: P = AB + CD + AC+ VD = a + b + a + c = 2*a + b + c. Example 4. Find the perimeter of an isosceles trapezoid if its side faces are 4 cm, and its bases are 2 cm and 6 cm. Solution: P = 2*a + b + c = 2 *4cm + 2 cm + 6 cm = 16 cm.

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Helpful advice
Nobody bothers you to find the perimeter of a quadrilateral (and any other figure) as the sum of the lengths of the sides, without applying the derived formulas. They are provided for convenience and ease of calculation. The method of solution is not an oversight; a positive result and knowledge of mathematical terminology are significant.

A circle is the location of points on planes that are identically distant from a given solid point, which is the center, at a certain distance called the radius. There is also an idea like diameter circles. To find it, use the instructions.

You will need

- calculator

Instructions

1. Double the radius D=2R. Diameter is a chord passing through the center of a circle, also diameter has the maximum length among all other chords allowed in a circle. In this case, we can conclude that it is equal to the sum of 2 radii of the same represented circle. This method is successfully used only if the problem contains radius data. Otherwise, choose something else to solve the problem.

2. Divide the circumference by Pi. Usually in mathematics this number is used as a designation for a certain irrational quantity. Pi is equal to 3.14. But this is a relative value that is used for comfort in simple calculations. The result is this completely simple formula: D=L/?. If there is data in the condition about the circumference, it can be applied and easily detected diameter given figure. Also, by slightly changing this formula, you can find the radius. It will be enough just to double the number Pi and also divide the total by the circumference. A simple and fairly universal formula for the radius will look like this: D=L/2?. In this case, there is again a proportional relationship between diameter ohm and radius. The main thing is that when finding them, do not confuse in which of the cases it is necessary to multiply the number Pi with two, and in which of them, say, you should not.

3. Consider the fact that diameter invariably relates to the radius as 2 to 1. Accordingly, formulas for finding the radius of a circle can be partially used. For example, knowing the area of a circle, you can divide it by Pi, extract the root from the result, and then double the resulting number. Actions in this case will look similar to this: 2SQR(S/?). This calculation option is also convenient if you have a limited area.

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Perimeter of any polygon is the sum of the measurements of all its sides. Perimeter problems rectangle found in the original geometry course. Sometimes, to solve them, the lengths of the sides need to be determined from indirect data. Familiarize yourself with the main types of problems and how to solve them.

You will need

- pen;
– paper for notes.

Instructions

1. Perimeter rectangle you can find out by adding up the lengths of all its sides. Because rectangle opposite sides are equal, the perimeter can be specified by the formula: p = 2(a+b), where a, b are adjacent sides.

2. Example problem: the condition says that one side rectangle has a length of 12 cm, and the second is three times smaller. You need to find the perimeter.

3. To solve, calculate the length of the 2nd side: b = 12/3 = 4 cm. Perimeter rectangle will be equal to: 2(4+12) = 32 cm.

4. 3rd example – in the problem only the length of one side and the diagonal are given. A triangle formed by two sides and a diagonal is a right triangle. Find the second side of the Pythagorean equation: b = (c^2-a^2)^1/2. After this, calculate the perimeter using the formula from step 1.

5. Fourth example – the length of the diagonal and the angle between the diagonal and the side are given rectangle. Calculate the side length from the expression: b = sina*c, where b is the side opposite the corner rectangle, с is its diagonal. Find the side adjacent to the corner: a = cosa*c. Knowing the lengths of the sides, determine the perimeter.

6. The fifth example is a rectangle inscribed in a circle with a given radius. The center of the circle lies at the point of intersection of the perpendicular bisectors of the polygon. For rectangle this coincides with the point of intersection of its diagonals. This means that the length of the diagonal is equal to the diameter of the circle or two radii. Next, depending on the conditions of the problem, find the sides of the polygon similar to step 2 or 3.

7. Sixth example: what is the perimeter? rectangle, if its area is 32 cm2? It is also known that one of its sides is twice as large as the other.

8. Square rectangle is the product of its 2 adjacent sides. Label the length of one side as x. The second one will be equal to 2x. You have an equation: 2x*x = 32. Having solved it, find x = 4 cm. Find the second side - 8 cm. Calculate the perimeter: 2(8+4) = 24 cm.

The perimeter of a flat geometric figure is the total length of all its constituent sides. A circle has only one side, and its length is usually called the circumference, and not the perimeter. Depending on the known parameters of the circle, this value can be calculated using various methods.

Instructions

1. To measure the perimeter of a circle on the ground, use a special device - a curvimeter. In order to find out the circumference of a circle using its support, the device must be simply rolled along it with a wheel. The same devices, but much smaller in size, are also used to determine the length of any curved lines, including circles, on drawings and maps.

2. If you need to calculate the circumference (L) from the famous diameter (d), multiply it by the number Pi (3.1415926535897932384626433832795...), rounding the number of digits to the required degree of accuracy: L=d*?. Because the diameter is equal to twice the radius (r), if this value is known, add the corresponding factor to the formula: L=2*r*?.

3. Knowing the area of the circle (S), you can also calculate the circumference (L). The ratio of these two quantities is expressed through the number Pi, therefore double the square root of the product of the area by this mathematical constant: L = 2*?(S*?).

4. If the area (s) of not each circle is known, but only a sector with a given central angle (?), then when calculating the circumference (L), proceed from the formula of the previous step. If the angle is expressed in degrees, the area of the sector will be ?/360 of the total area of the circle, which can be expressed by the formula s*360/?. Substitute it into the above equation: L = 2*?((s*360/?)*?) = 2*?(s*360*?/?). However, radians, rather than degrees, are often used to measure the central angle. In this case, the area of the sector will be?/(2*?) of the total area of the circle, and the formula for calculating the circumference will take the following form: L = 2*?((s*2*?/?)*?) = 2*? (s*2*??/?) = 2*?*?(2*s/?).

5. Apply similar proportions when calculating the circumference (L) from the known arc length (l) and the corresponding central angle (?) - in this case the formulas will be simpler. When the central angle is expressed in degrees, use the following identity: L = l*360/?, and if it is given in radians, the formula should be: L = l*2*?/?.

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Tip 10: Furniture for a children's room: features of choice, requirements

Children need an area where they can spend time doing children's activities and games. It is important to design the child’s personal space in such a way that he is comfortable and comfortable. One of the primary tasks when arranging a children's room is a positive choice of furniture. It should not only be beautiful, but functional and harmless to the health of children.

House inside a house

Don’t rush to decorate your children’s room in a traditional style. Ask your child how he would like his corner to be, where he would be extremely comfortable and happy to be, look through the catalogs of current children's furniture. The best option today is to organize the interior using transformable furniture. As a result of this arrangement, in a day the children’s room will be able to turn into a store, a comfortable house, a tent, a boat and much more - it all depends on the children’s mood. As the baby grows, different modifications are allowed. Transformable furniture will save space and money because it will serve the child until he is able to purchase furniture for himself. Children will definitely be captivated by multifunctional structures made up of slides from which they can slide down, bunk beds, ladders, shelves, bedside tables and cabinets, and voids and niches in cascades of multi-level modules used instead of a standard wall will make the room more interesting. This atmosphere encourages communication with parents and peers who come to play. The baby will learn to create his own world on his own, without fear that he will be scolded for bedlam. In the future, this will make it easier for him to adapt to adulthood. Thrifty parents should purchase furniture that changes as the child grows. For example, these could be beds that turn into a sleeping place for a schoolchild, tables and chairs with adjustable tabletops and seats.

Color and materials

For the manufacture of children's furniture, high-quality materials must be used, say MDF, but it is better if it is natural wood. An excellent and inexpensive material is pine, but it is quite soft, and such furniture will leave dents after minor mechanical impacts. However, parents who are ready to renew wooden products over time by priming and painting them can bravely choose pine furniture. The paints used to paint children's furniture must be environmentally friendly. If you are not embarrassed by the issue of price, equip the children's room with furniture made of birch, beech or ash. Take care of a comfortable color scheme in the nursery. Choose furniture in pastel colors, say blue or clear green. Such shades have a reflectance of 40-60%, and this increases the normal lighting of the room. However, if children like shiny colors, do not deny them this. But be careful not to have too many intense shades.

Safety

Of course, furniture should provide children with safety. Depending on the age of the child, his bed, if it is high, should have high sides and be equipped with limiters. Furniture with handles, corners and other fittings made not of metal, but of plastic, allows you to avoid various injuries. For a child under 10 years old, you should not choose a cabinet with glass doors. All fastenings must be strong, preventing the furniture from swaying. Therefore, when purchasing new products, carefully check the quality of the joints and look at the condition of the fittings.