Question

A right circular cone, of height 12 ft, stands on its base which has diameter 8 ft. The tip of the cone is cut off with a plane which is parallel to the base and 9 ft from the base. With π = 22/7, the volume, in cubic ft, of the remaining part of the cone is

Answer 1

Correct Answer: 198

We are given that diameter of base = 8 ft. Therefore, the radius of circular base = 8/2 = 4 ft
In triangle OAB and OCD
OA/AB = OC/CD
⇒ AB = 3×4/12 = 1ft
Therefore, the volume of remaining part = Volume of entire cone - Volume of smaller cone
⇒ 1/3×π×42×12-1/3×π×12×3
⇒ 1/3×π×189
⇒ 22/7×3×189
⇒ 198 cubic ft