# The area of the rectangle is 40 cm. The length of one side of it is 8 cm. Find the perimeter of this rectangle.

July 29, 2021 | education

| From the condition, we know the area of the rectangle is 40 cm2, as well as the length of one of its sides is 8 cm.

In order to find the perimeter of a rectangle, we need to know the lengths of its sides.

We know the area of the rectangle, which can be found by the formula S = a * b, from here we will find the unknown side.

Substitute and calculate:

40 = 8a;

a = 40: 8;

a = 5 cm length of the second side of the rectangle.

Let’s recall the formula for finding the perimeter of a rectangle and calculate it.

P = 2 (a + b) = 2 (5 + 8) = 2 * 13 = 26 cm rectangle.

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