Question

A homeowner wants to increase the size of a rectangular deck that now measures 14 feet by 22 feet. The building code allows for a deck to have a maximum area of 800 square feet. If the length and width are increased by the same number of feet, find the maximum number of whole feet each dimension can be increased.

Answer 1

Answer:

10.6 feet

Step-by-step explanation:

Length = 22ft

width= 14ft

Maximum area = 800 sq. ft

Let X be increase in the number of feet for the length and width.

The new length = (22 + x) ft

New width= (14 + x) ft

Area = (22+x)(14+x) ≤ 800

308 + 36x + x^2 ≤ 800

x^2 + 36x + 308 - 800 ≤ 0

x^2 + 36x - 492 ≤ 0

Solve using quadratic equation

x = (-b +/- √b^2 - 4ac) / 2a

a= 1, b = 36, c= 492

x = (-36 +/- √36^2 - 4*1*-492)/ 2*1

= (-36 +/- √1396 + 1968) / 2

= (-36 +/- √3264) / 2

= (-36 +/- 57.13) / 2

x = (-36 + 57.13)/2 or (-36 - 57.13)/2

x = 21.13/2 or -93.13/2

x = 10.6 or -31.0

x = 10.6 ft

The length and width must increase by 10.6 ft each