Question

Sharon is making rectangular posters. Each poster has an area of 4800 square inches and the length is 20 inches more than the width. Find the length and width of her poster.

Answer 1

Area of a rectangle is LxW. We let x = width and x+20 = length. Using the formula we will evaluate;

A = LxW

4800 = (x+20)(x)

x² + 20x – 4800 = 0

We will get the factors of it to determine x values, in this case, we are only looking at the positive x value since are dealing with the area.

x² + 20x + 4800 = 0

(x+80)(x-60) = 0

(x + 80) = 0 | (x-60) = 0

x = - 80 | x = 60

x = 60, this is the width

x +20 = 80, this is the length