Question

The area of the curved surface of a cone of radius 2r and slant height $\frac{l}{2}$, is

(a) $\mathrm{\pi }rl$

(b) 2$\mathrm{\pi }rl$

(c) $\frac{1}{2}\mathrm{\pi }rl$

(d) $\mathrm{\pi }(r+l)r$

Answer 1

The formula of the curved surface area of a cone with base radius ‘r’ and slant height ‘l’ is given as

Curved Surface Area = πrl

Here the base radius is given as ‘2r’ and the slant height is given as ‘’

Substituting these values in the above equation we have

Curved Surface Area =

= πrl

Hence the correct choice is (a).