The height of the larger cylinder is 12 feet. The height of the smaller cylinder is 12 / 3 = 4 feet.
Volume of a cylinder formula: V = pi x r^2 x h
r = 216 / 2 = 108 / 12 = 9 feet
V = pi x (9)^2 x 4
V = pi x 81 x 4
V = 321pi = 1017.88 ft^3
Hope this helps!! :)