Question

Curved surface area of a cone is $308{cm}^2$ and its slant height is $14cm$. Find total surface area of the cone.

• A. $462{cm}^2$
• B. $262{cm}^2$
• C. $432{cm}^2$
• D. $762{cm}^2$

Answer 1

The correct option is A $462{cm}^2$

Curved surface area of a cone $=\pi rl$ where r is the radius of the cone and l is the slant height.
Hence, CSA of this cone, $=\frac{22}{7}\times r\times 14=308$
$=>r=7cm$

Hence, radius of the base of the cone is $7cm$.

Total surface area of a cone $=\pi r(r+l)$ where r is the radius of the cone and l is the slant heght.
Hence, TSA of this cone, $=\frac{22}{7}\times 7\times (7+14)=462{cm}^2$