The length of a rectangle is 9 feet longer than it is wide. If each side is increased 9 feet, then the area is multiplied by 2. What was the size of the original rectangle?

Question

The length of a rectangle is 9 feet longer than it is wide. If each side is increased 9 feet, then the area is multiplied by 2. What was the size of the original rectangle?

Answer 1

Don't forget to answer the original question: What is the size (dimensions) of the original rectangle? w=18 and l= w+9 means l=27. The rectangle is 18 by 27. :)

Answer 2

l = w + 9

(l+9)(w + 9) = 2 lw

Substituting,

(w+9+9)(w+9) = 2(w+9)(w)

(w+18)(w+9) = 2(w+9)(w)

We have a short-cut, because we have w+9 on both sides, so we can divide by this.

w+18 = 2w

w = 18