Question

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

Answer 1

Option c (choice 3) is the correct choice 

Answer 2

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:

`(1)/( 3) \pi (7.5^(2))(19) - (1)/(3) \pi (3.5^(2))(8)`