Question

Mike is pouring a two foot cement sidewalk around the perimeter of his swimming pool. His swimming pool measures 6 feet by 14 feet. If he plans for the sidewalk to be 9 inches deep, what volume of cement is needed for the sidewalk?

Answer 1

the correct answer is B) 72^ft 3

Answer 2

9 inches * 1 foot / 12 inches
= 3/4 feet deep

Area of the sidewalk:
= the sides of the pool * the width of the sidewalk + the corners of the sidewalk (width * width)
= 2 sides * 6 (feet / side) * 2 feet + 2 sides * 14 (feet / side) * 2 feet + 4 corners * (2 feet * 2 feet / corner)
= 12 feet * 2 feet + 28 feet * 2 feet + 4 * 2 feet * 2 feet
= 24 feet^2 + 56 feet^2 + 16 feet^2
= 96 feet^2

Volume:
= 96 feet^2 * 3/4 feet
= (96 * 3 / 4) feet^3
= (19 * 3) feet^3
= 57 feet^3