One side of the rectangle is 4 cm 5 mm the other 3 cm 2 mm, find its perimeter.

Imagine the value of the sides of the rectangle in millimeters: since 1 cm = 10 mm, then one side is 4 cm 5 mm = 4 * 10 mm + 5 mm = 40 mm + 5 mm = 45 mm, and the second side is 3 cm 2 mm = 3 * 10 mm + 2 mm = 30 mm + 2 mm = 32 mm. The perimeter of a rectangle is the sum of all its sides. Therefore, P = 45 mm + 45 mm + 32 mm + 32 mm = 154 mm = 15 cm 4 mm.
The answer is the perimeter of the rectangle is 15 cm 4 mm.