The side of the rectangle is 5 cm, the perimeter is 18 cm. What is the other side of the rectangle?

To find the other side of a rectangle, recall the formula for the perimeter of a rectangle:

P = (a + b) * 2, where a and b are the sides of the rectangle.

Let us express one of the sides through this formula:

a = P: 2 – b.

Let’s find the unknown side of the rectangle:

a = 18: 2 – 5;

a = 9 – 5;

a = 4 cm – the second side of the rectangle.

Answer: the second side of the rectangle is 4 cm.