Concrete Tank

Given: A circular concrete tank with an inside diameter of 28 feet, a wall thickness of 6 inches, and a tank wall height of 10 feet calculate the net volume of concrete in the tank wall.

A. Between 9 and 11 cubic yards.
B. Between 11 and 13 cubic yards.
C. Between 13 and 15 cubic yards.
D. More than 15 cubic yards.

Answer: D

3.14 x r x r x d / 27 = cy
Take inside at diameter of 28′, outside of 29’… subtract missing area from entire area.