Question

A frustum is formed when a plane parallel to a cone’s base cuts off the upper portion as shown.

Answer 1

The volume of a cone is
V = (1/3) π r² h
where r =  radius of the base
h =  the height.

The volume of the frustum is
(1/3)π(7.5²)(11+8) - (1/3)π(3.5²)(8)
=(1/3)π(7.5²)(19) - (1/3)π(3.5²)(8)

The 3rd choice is the correct answer.

Answer:
$\frac{1}{ 3} \pi (7.5^{2})(19) - \frac{1}{3} \pi (3.5^{2})(8)$

Answer 2

Option c (choice 3) is the correct choice