Question

The curved surface area of the cone is $\pi rl,$ then the total surface area of the cone is:

• A. $\pi r(r+l)$
• B. $\pi rl(r+l)$
• C. $2\pi rl(r-l)$
• D. $2\pi r^{2}l(r+l)$

Answer 1

The correct option is A $\pi r(r+l)$

Given: Curved surface area of cone $=\pi rl$

We know, the total surface area of cone $=$ curved surface area of cone $+$ area of circular base.

and area of circular base $=\pi r^2$

Then, the total surface area of cone $=$ $\pi rl+\pi r^2$

$=\pi r(l+r)$