Question

How do I figure this out?

Answer 1

Answer: 20.5

Form your equation. The formula for perimeter is (2l)(2w) or l + l + w + w, where l = length and w = width.
(l - 5) + (l - 5) + (l) + (l) = 72

Simplify and solve your equation.
4l - 10 = 72
4l = 82
l = 20.5

Since l = length, length = 20.5 and width = 15.5

You can check your work, too:
20.5 + 20.5 + 15.5 + 15.5 = 72