Question

The radius and slant height of a cone are in the ratio $4:7$. If its curved surface area is $792{cm}^2$, find its radius. (Use $\pi =\frac{22}{7}$)

• A. $12cm$
• B. $14cm$
• C. $16cm$
• D. $10cm$

Answer 1

The correct option is A $12cm$

Let the radius of the cone be $4a$ cm and slant height $=7a$ cm.

Curved surface area of a cone $=\pi rl$

Hence, CSA of this cone, $=\frac{22}{7}\times 4a\times 7a=792$

$=>a=3cm$

Hence, radius $=4a=12cm$