A right circular cone has slant height $30$ cm and base radius $8$ cm. What is its total surface area? (Use $\pi =\frac{22}{7}$).

Step-by-step solution

1. Compute the base area: $A_{\text{base}}=\pi r^2=\frac{22}{7}\times 8^2=\frac{22}{7}\times 64=\frac{1408}{7}=201.14{\text{ cm}}^2$.
2. Compute the lateral area: $A_{\text{lat}}=\pi rl=\frac{22}{7}\times 8\times 30=\frac{22}{7}\times 240=\frac{5280}{7}=754.29{\text{ cm}}^2$.
3. Add the two areas: $A_{\text{total}}=A_{\text{base}}+A_{\text{lat}}=\frac{1408+5280}{7}=\frac{6688}{7}=955.43{\text{ cm}}^2$.

Concept tested: Total surface area of a right circular cone

Published 13 October 2026 · How this solution was prepared and checked