# The perimeter of the square is equal to the perimeter of the rectangle. Square area 81 cm2.

The perimeter of the square is equal to the perimeter of the rectangle. Square area 81 cm2. The length of the rectangle is 2 times longer than the width. Find the area of a rectangle

1. Find the side of the square, for this we extract the square root from the value of the area.

√81 = 9 (cm) side of the square.

2. Find the perimeter of the square by multiplying the length of its side by the number of sides since they are equal in the square.

9 * 4 = 36 (cm) perimeter of the square.

3. Let the width of the rectangle be x cm, then the length of the rectangle is 2 * x = (2x) cm.

Find the semi-perimeter of the rectangle x + 2x = (3x) cm, and by condition, the semi-perimeter.

36/2 = 18 (cm).

Let’s compose and solve the equation.

3x = 18;

x = 18/3;

x = 6 cm width of the rectangle, then the length is 6 * 2 = 12 cm.

4. Find the area of ​​the rectangle by multiplying the length by the width.

6 * 12 = 72 (cm2). 