The length of the rectangle is 5 times its width. Find the sides of the rectangle if its perimeter is 84cm.

Let’s denote the width of the rectangle by the symbol X.

Then the length of the rectangle will be 5 * X;

The perimeter of the rectangle is:

2 * (X + (5 * X)) = 2 * 6 * X = 12 * X = 84 cm;

X = 84/12 = 7 cm.

Let’s find the length of the rectangle:

5 * X = 5 * 7 = 35 cm.

Answer: the width of the rectangle is 7 cm, the length is 35 cm.