At a kennel, each dog run i a rectangle whose length is 4ft more than twice its width. Each run encloses 240 square feet. What are the dimensions of the run?

Question

At a kennel, each dog run is a rectangle whose length is 4ft more than twice its width. Each run encloses 240 square feet. What are the dimensions of the run?

Answer 1

Let x = the width

Let 2x + 4 = the length 

A = lw

240 = x(2x + 4)

240 = 2x² + 4x

2x² + 4x - 240 = 0

x² + 2x - 120 = 0

(x - 10)(x + 12) = 0

x - 10 = 0    or  x + 12 = 0       x = -12, illogical answer

x = 10 feet - width

2(10) + 4 = 24 feet - length