Question

Twice the length of a rectangle is equal to four times its width. The perimeter of the
rectangle is 80 inches. Find the dimensions of the rectangle.

Answer 1

Let l and w be the length and width of the rectangle. We are given the proportion 2l=4w, which implies l=2w.

The perimeter of a rectangle is given by 2(l+w). We know that the perimeter is 80, and we can plug l=2w to get

$2(l+w)=80 \iff 2(2w+w)=80 \iff 3w=40 \iff w=\dfrac{40}{3}$

Which, in turn, implies that

$l=2w=\dfrac{80}{3}$