Answer: The correct answer is c. 1416.9 ft3. The volume of a cylinder is calculated as πr^2h, where r is the radius and h is the height. The radius of the cylinder is half of the diameter, so in this case it would be 19/2 = 9.5 feet. The volume of the foundation would be π * 9.5^2 * 5 = 712.39 cubic feet. So you would need 712.39 cubic feet of concrete to pour the foundation.
Explanation: