The length of a rectangle is 3 centimeters less than its width. What are the dimensions of the rectangle if it’s area is 154 square centimeters?

Answer 1

We start by putting what we know into equations:

L = W-3

A = L x W

Now we substitute in the values:

154 = W(W-3) Multiply by W

154 = W(W-3)= W² - 3W Substract 154 to get the quadratic equation equal to 0.

0 = W² - 3W - 154 Factor the quadratic equation or use the quadratic formula. However,

it is known that 11 x 14 = 154

(W+ 11)(W- 14) For the signs, the larger number will have to go with the negative

sign to obtain the -3W. Solve for W.

W = -11 W = 14 Because the width can not be negative, 14 is the width

W = 14 centimeters

L = 14-3 = 11 centimers.