Guide
1
Calculation sides of the square.Formula area of ​​the square a² where a - side of the figure.To calculate the area of ​​a square you need to know only one side, as all its sides are equal.Hence calculate the direction is very simple: √a.Example: The area is 49. Highlight the square root of 49. Answer: 7.
2
Calculation sides of the rectangle.Find the part of the figure, knowing only the value of the area, it is impossible.You need to know one more value - its perimeter.Here is an example, the area is 12, and the perimeter 14.
Mark the side of the rectangle the "x" and "y".The formula of calculating the perimeter P = 2 (a + b), substitute the values ​​of our task 2 (x + y) = 14.
The formula calculating the area S = ab substitute the values ​​of our problem xy = 12, t. E
. = 12 x / y.Substitute the value of "x" in the equation 2 (x + y) = 14.
get 2 (12 / y + y) = 14.Transfer the like 12 / y + y = 14/2.12 / y + y = 7.Multiply both sides by "y".Get 12 + y ^ 2 = 7V.y 2-7u +12 = 0 - quadratic equation, think through discriminant.At the root of the equation y 2 = 4;y = 3.
A. sides of the rectangle are 3 and 4 cm respectively.
3
Calculation sides of the diamond.To find out the part of lozenge (EWYP), in addition to the space you need to have more any value.For example, the height - WH, it is the length of the perpendicular dropped from the vertex (W) on the side (EP).It should be remembered that the sides of the rhombus are equal.In this case it is very easy to determine the direction of the rhombus (EW).It is known that diamond may be represented as two triangles EWP and PWY, the area of ​​each of which is equal to half the product of the height of the base.One can conclude that the area of ​​the rhombus is equal to the product of the height to length of the side.This yields a simple formula to calculate the length of side diamonds: it is necessary to divide the area by the length of the height - | EW | = S / | WH |.Example: Let the area of ​​the rhombus EWYP is 20. The height WH = 5.Substitute values ​​in the above formula: | EW | = 20 / | 5.Answer: The party is 4.
4
Calculation sides of an equilateral triangle.In order to get his way (and all of its sides are equal), the area in addition to the need to know the height.If you know these two quantities, then you can make payment by this formula: b = 2S / h, where b - side of the triangle, S - area, h - height.Example: Let the area of ​​an equilateral triangle ABC is equal to 25. The height BH = 5.
Substitute the values ​​into the formula: b = 2 * 25/5.Answer: The party is 10.