One side of a parallelogram is four times the other; find the smaller side if the parallelogram has a perimeter of 40 cm.

Let’s denote the length of the shorter side of this parallelogram through x.

According to the condition of the problem, one of the sides of this parallelogram is four times larger than the other, therefore, the length of the larger side of this parallelogram is 4x.

It is also known that the perimeter of this parallelogram is 40 cm, therefore, we can draw up the following equation:

2 * (x + 4x) = 40.

We solve the resulting equation and find the length of the shorter side of this parallelogram:

2 * 5x = 40;

10 * x = 40;

x = 40/10;

x = 4 cm.

Answer: the length of the smaller side of this parallelogram is 4 cm.