Math
posted by Stephanie .
The length of a rectangle is twice the width. The perimeter is 84 cm more than its width. Find the dimensions.

y = 2w
2w+2y = w+84
2w+4w = w + 84
5w = 84
w = 84/5
so, y=168/5
check:
2(w+y) = 2(252/5) = 504/5 = 84/5 + 84