The perimeter of the parallelogram is 56 cm. Find its sides if the sum of its two sides is 20 cm.

In order to find the lengths of the sides of a parallelogram, we will compose and solve an equation.

Let’s see what we know from the problem statement. It is known that the perimeter of a parallelogram is 56 cm. It is also known that the sum of its two sides is 20 cm.

Apparently these are opposite sides and they are equal to each other. Find one of the sides: 20: 2 = 10 cm.

Let’s use the variable x to denote the length of the second side.

We look for the perimeter by the formula:

P = 2 (a + b);

2 (x + 10) = 56;

x + 10 = 56: 2;

x + 10 = 28;

x = 28 – 10;

x = 18 cm length of the second pair of sides.