# Advice 1: How to find the perimeter if you know area

Area and perimeter - basic numerical characteristics of any geometric shapes. Finding these values is facilitated by the generally accepted formulas in which you can calculate through one another with little or no additional initial data. Instruction
1
Prjamougolnosti: find the perimeter of a rectangle if you know that the area is equal to 18, and the length of a rectangle is 2 times the width.Solution: write the formula for area of a rectangle S = a*b. The statement b = 2*a, hence 18 = a*2*a, a = √9 = 3. It is obvious that b = 6. According to the formula the perimeter is equal to the sum of all the sides of the rectangle P = 2*a + 2*b = 2*3 + 2*6 = 6 + 12 = 18. In this problem the perimeter is matched by value with the area of the figure.
2
Quadratscha: find the perimeter of a square if its area is 9.Solution: by formula the area of a square S = a^2, hence find the length of side a = 3. The perimeter is equal to the sum of the lengths of all sides hence P = 4*a = 4*3 = 12.
3
Treugolnika: given an arbitrary triangle ABC, the square of which is equal to 14. Find the perimeter of a triangle, if drawn from the vertex B, the altitude divides the base of the triangle into segments of length 3 and 4, see the Solution: by formula the area of a triangle is half the work of the Foundation to the height, i.e., S = ½*AC*BE. The perimeter is equal to the sum of the lengths of all sides. The length of the side AC find the folding of the lengths AE and EC, AC = 3 + 4 = 7. Find the height of the triangle BE = S*2/AC = 14*2/7 = 4.Consider the right triangle ABE. Knowing the legs AE and BE, we can find the hypotenuse by the formula of Pythagoras, AB^2 = AE^2 + BE^2, AB = √(3^2 + 4^2) = √25 = 5.Consider the right triangle BEC. By the formula of Pythagoras BC^2 = BE^2 + EC^2, BC = √(4^2 + 4^2) = 4*√2.Now known the lengths of all sides of the triangle. Find the perimeter of their sum P = AB + BC + AC = 5 + 4*√2 + 7 = 12 + 4*√2 = 4*(3+√2).
4
Ukrainetoday: it is known that the area of the circle is 16*PI, find its perimeter.Solution: write the formula for area of a circle S = π*r^2. Find the radius of the circle r = √(S/π) = √16 = 4. According to the formula of the perimeter P = 2*π*r = 2*π*4 = 8*π. If we assume that π = 3.14, P = 8*3.14 = 25.12.

# Advice 2 : How to calculate the area of a room

Sooner or later there comes a time when you need to do repairs. They say that if you do repairs only in one room, then the number of carries dirt this process is similar to repair a flat. Therefore, it is better to venture on repair of all housing. But whatever you decided to do this, you initially have to calculate the room area and an estimate of the upcoming costs. Instruction
1
To calculate the area of a room, armed with a long tape measure. Fortunately, measuring the area of most Russian apartments do not cause major difficulties, because they were built on standard projects and all kind of resemble each other. Using a ruler measure the length and width of the room. Record the result in a notebook.
2
If your room lacks any protrusions or, on the contrary, holes in the walls, and shape of the room is a regular rectangle, to calculate area, multiply the resulting measurements to each other. This figure will be the total area of the room.
3
However, if your room is located, for example, part of a closet or in a room with some pillars, then you have to exclude these dimensions from the obtained measurement results. For this additionally calculate the area of each protruding element of the room and subtract it from the total area of the room.
4
Guided by the same principle, calculate the area of all room walls. To exclude the size of door openings and Windows, and also add an additional area of the walls arches such as under radiators. By doing thus, all the necessary measurements, you will get the exact area of the room, all its walls and floors and be able to calculate the amount of Wallpaper, linoleum or other materials you will need for repair.

# Advice 3 : How to find the area of a room

It is often necessary to know exactly the area of the room. This may be required when repair to calculate the amount of paint or floor covering, when buying new furniture or remodeling apartments. In the accompanying documents to the apartment or house is usually stated a total useful area of housing, therefore the size of each room separately will have to calculate yourself. Instruction
1
As you know from the school course of geometry to calculate the area of a rectangle, you multiply the length by the width. Accordingly, in order to find out the area of a room, multiply the length of its sides.
2
First begin by measuring the sides of the room. Do it better by using construction tape, which has a sufficient length and keeps a smooth shape. The length and width of the room measure along the walls. This frees up space near the wall and put the tape measure along the floor. Important to make sure that the measuring tapes are not twisted and not stretched excessively. The obtained data it is better to write down on a piece of paper so you don't have to measure again.
3
By measuring both sides of the room – length and width, and do the necessary calculations. For example, if the longest side is 5 m and 3 m, the area of the entire room will be 5x3 = 15 sq. m. it Should be note that if the lengths are always measured in meters, then the area of the surface of the floor or ceiling only in square meters.
4
In the absence of in house construction and roulette you can use to measure ordinary tailor's meter. But it is important to remember that in this case the accuracy of the results obtained will be much higher, because the tape bends easily and folds. Moreover, it is much shorter, so the length will have to measure, consistently moving a centimeter at uniform intervals.

# Advice 4 : How to calculate the area of walls

Repair is a good thing. The results are pleasing: new floors, ceilings, Wallpaper... Only there is one little "but"... If you do it yourself, the repair becomes a torment: to choose the right color, choose the Wallpaper, purchase the desired amount of material. In order not to spend extra money on paint, Wallpaper, etc, you must be able to correctly calculate the area of the treated surface. You will need
• Measuring tape
Instruction
1
Calculate area of walls in one room is very simple.
The total area needs to be folded from square of all the (usually) four wallsOK, they're all the same, but some have Windows, doors and similar structures. S=S1+S2+S3+S4.
2
To find the area of one of the walls, you should multiply the height of the walls of theing on its length. If it does not, it will be the first area S1. Similarly, the calculated area of the other three walls S2, S3, S4. And the area of those walls, where there is, for example, window, calculated as: measured width and length of the window are multiplied by each other, it turns out the square window, the size of a wall, s is subtracted the area of the window, this will be the area of the wallss, where encased window, door, etc.

# Advice 5 : How to calculate the area of a room

If you are going to sell the apartment, to make repairs in the room, change the interior and furniture, often have to answer the question: "What is the area of the room in the apartment?" And an approximate figure is irrelevant here. The sofa does not fit into the corner, the lack of linoleum or carpet that can permanently ruin the mood. There are errors in the documentation for the apartment. To trouble passed, get the definition of the area of the room alone. You will need
• - the tape or the tape;
• pencil.
Instruction
1
If the room is a classic rectangle, you only need a few minutes to calculate the area. Measure the room's length and width of the room. Then, multiply the two numbers. For example, the length of the room was a 5.2 m and width 3.5 m. Then the area of the room is equal to 18.2 m.
2
If the room is not a square or rectangle, and has a more complex form, the calculation is simple. Divide the room into rectangular pieces (for example, a niche and the room itself). In a similar way calculate the area of each space and add two numbers. If the room area was 14 m, and niche – 4 m, the area of the entire room is 18 m.
3
In new buildings, there are rooms are very complicated and irregular shape. In this case it is better to use the services of specialists BTI. If you are determined to cope with the job yourself, try to divide the room into familiar shapes: triangles, squares, trapezoids. Use the online service for calculating area of complex shapes. Enter the numbers, get the result.