35cm × 2 = 70cm The shortest side of this rectangle is 14cm, so you know that there are two sides with a measurement of 14cm. 14cm × 2 = 28cm Add both answers together for the perimeter.

How do you work out a perimeter? VO: To find the perimeter of a rectangular room, you need to measure the length and double it. Then measure the width, and double that, and add the answers together.