I am very confused on this question

Answer:
955.0 ft^3 remains in A
Step-by-step explanation:
Volume of a cylnder = V = pi r^2 h
A: pi (9)^2 *9 = 729 pi (Note: You are given DIAMETER...need RADIUS)
B: pi (5)^2 *17 = 425 pi
A - B = pi ( 729 - 425) = 955.0 ft^3 remains