The perimeter of the rectangle is 24 cm, and the side length is 4 cm. Find the area of the rectangle.

Given:

Rectangle;

a = 4 cm;

P = 24 cm;

Find: Area, side b;

Solution:

The perimeter is the sum of the lengths of all sides. The rectangle has four sides. Respectively:

P = (a + b) * 2;

Substitute the values:

24 = (4 + b) * 2;

We solve the equation with one unknown:

4 + b = 24/2;

4 + b = 12;

b = 12 – 4;

b = 8 cm (second side of the rectangle);

The area is found by the formula:

S = a * b;

S = 4 * 8;

S = 32 cm2;

Answer: the area of the rectangle is 32 cm2;