Question

The length of a rectangular portrait is 2.5 times the width. The perimeter is 28 feet.

What is the length of the portrait?

Answer 1

l=2.5*w, p=2l+2w. Plug in your known value for l, p=2(2.5w)+2w=5w+2w=7w. Now solve for w, p/7=(7w)/7=w. Plug in your perimeter, w=p/7=28/7=4. Plug in your width into your equation for length. l=2.5w=2.5(4)=10. Your length is 10 feet.