Question

The owner of an office building is expanding the length and width of a parking lot by the same amount. The lot currently measured 120ft by 80ft, and the expansion will increase its area by 4,400ft^2. By how many feet should the parking lot be increased?

Answer 1

20

Explanation:

The current area is 120(80)=9600 and he want to expand it by 4400 so that the new area will be 9600+4400=14000

14000=(120+x)(80+x)

14000=9600+200x+x^2

x^2+200x-4400=0

x^2-20x+220x-4400=0

x(x-20)+220(x-20)=0

(x+220)(x-20)=0, since x is an increase it must be greater than zero so

x=20ft

(120+20)(80+20)=14000ft^2