Surface Area Of A Right Circular Cone

The total surface area of a cone is given by the formula:

where:

• is the radius of the base,
• is the slant height.

Step 1: Given values

Diameter of the base = 24 m → Radius ( ) = m
Slant height ( ) = 21 m

Step 2: Substituting into the formula

Final Answer: The total surface area of the cone is , which corresponds to option .