Question

A garden is in the shape of a square with a perimeter of
64
feet. The garden is surrounded by two fences. One fence is around the perimeter of the garden, whereas the second fence is
2
feet from the first fence on the outside. If the material used to build the two fences is
$
1.17
per foot, what was the total cost of the fences?

Answer 1

The perimeter of a square is the sum of its sides and they are all equal, so to obtain the length of each of them we divide the perimeter of the first fence between 4:

 P1= 64 feet/4 sides

 P1= 16 feet

 Then, the length of each side of the second fence will increase 2 feet at each end, as shown in the figure. We have then that the perimeter of the second fence is:

 P2 = 20 feet x 4 sides

 P2 = 80 feet

 The sum of the perimeters of both fences is:

 PT = P1 + P2

 PT = 64 feet + 80 feet

 PT = 144 feet

 Total cost = 1.17 $ x 144 feet

 Total cost = 168.48 $

 The total cost of the fences was $ 168.48