The perimeter of a rectangle is 88cm. Its shortest side has a length of 19cm. State the length of the longest side.

Answer 1

If one side of the rectangle has a length of 19cm, we would double that to get 38cm. Because perimeter of a rectangle is 2(length+width), we can now work backwards and think, 88-38=50cm. The last two sides have to equal 50cm together, so each side is 25cm. Therefore, the length of the longest side is 25cm.