Christina B. answered • 03/14/19
Experienced, Positive, and Effective Tutor with an M.Ed.
The perimeter of a rectangle is two times its length added to two times its width. If I write this with symbols, it looks like P = 2l+2w. That might help us to start thinking about this problem. You can plug in the information that you know to help you solve for the information that you don't know.
Let's change P to 16 and w to 5. Now the equation is 16 = 2l + 2x5. We know that 2x5 is 10, so let's put that into the equation. 16 = 2l + 10. So, something added to 10 will give you 16. I bet you can solve for that without me giving you the answer. Just don't forget that a rectangle has two of each side!
