The perimeter of the rectangle is 56 cm. One of its sides is 7 cm. Find the area of the rectangle.

You need to know that the perimeter of a rectangle is the sum of all its sides.

We know that 1 side of the rectangle = seven centimeters. From this we conclude that the 2nd side is also = seven centimeters.

1) 7 + 7 = 14 cm – the sum of 2 sides of a geometric figure.

2) 56 – 14 = 42 cm – the sum of the other 2 sides.

Find out the length of 1 side.

3) 42/2 = 21 cm – this is the length of 1 side.

We are looking for the area of the rectangle. Remember that: s = a * b.

4) 7 * 21 = 147 cm square.

Answer. The rectangle is 147 cm square.