The perimeter of the rectangle is 40, and one of its sides is 5cm, or the length of the other side

The perimeter of the rectangle is 40, and one of its sides is 5cm, or the length of the other side of the rectangle. Find the area of the rectangle.

Answer: 15 cm; 75 cm².

1. Perimeter is the sum of the lengths of all sides. There are 4 sides in a rectangle. In addition, his opposite sides are equal to each other. If we subtract the lengths of the known sides (5 cm) from the value of the perimeter, we get twice the length of the other sides:

40 – 5 – 5 = 30 cm.

By dividing this result in half, we get the length of the other two sides:

30/2 = 15 cm.

2. Knowing the lengths of all sides, we can calculate the area. The area of a rectangle is the product of its length and width. Then:

15 * 5 = 75 cm².