Chapter E, Problem 12.14EX

To determine

To find the total surface area of the cone.

Answer to Problem 12.14EX

Option (b)

Explanation of Solution

Given information: The radius and the slant height of the cone is 9 and 12 units.

Concept used:

  $\text{Total surface area of the cone}=\pi rl+\pi r^2$

  $\text{Total surface area of the cone}=108\pi +81\pi =189\pi$

Hence, the total surface area of the cone is $189\pi$ square units.