A frustum is formed when a plane parallel to a cone’s base cuts off the upper portion as shown.
A cone is shown. The top of the cone is cut off to form a frustum of the bottom portion. The cone has a radius of 3.5 and a height of 8. The frustum has a height of 11 and a radius of 7.5.
Which expression represents the volume, in cubic units, of the frustum?