The length of a rectangle is three times its width.If the perimeter of the rectangle is 40 cm, find its length and width

Let's denote the width of the rectangle as x. According to the problem, the length of the rectangle is three times its width, so we can denote the length as 3x.

The formula for the perimeter of a rectangle is P = 2l + 2w, where l is the length and w is the width.

Substituting the given values into the formula, we get:

40 = 2(3x) + 2x 40 = 6x + 2x 40 = 8x

To find the value of x (the width), we divide both sides of the equation by 8:

x = 40 / 8 x = 5 cm

So, the width of the rectangle is 5 cm.

To find the length, we substitute x = 5 into the length expression 3x:

3x = 3*5 = 15 cm

So, the length of the rectangle is 15 cm.