A square with a side of 12 cm and a rectangle with one side equal to 10 cm

A square with a side of 12 cm and a rectangle with one side equal to 10 cm have equal perimeters. What is the unknown side of the rectangle?

The formula for the perimeter of a square is:

P = (a + b) * 2 = (a + a) * 2 = 2a * 2 = 4a, where a is the side of the square.

Let’s calculate the perimeter of the square:

4 * 12 = 48 cm – the perimeter of the square.

Formula for the length of the side of a rectangle:

a = P: 2 – b.

Find the second side of the rectangle:

a = 48: 2 – 10 = 24 – 10 = 14 cm – unknown side of the rectangle.

Answer: The second side of the rectangle is 14 centimeters.