Question

What is the total surface area of a cone of base radius r, height h and slant height l ?

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

Answer 1

The correct option is C $\pi rl+\pi r^2$


The curved surface area of a cone of base radius r, height h and slant height l is $\pi rl$.
So, total surface area = curved surface area + base area
Here, base is a circle of radius r. So, area of base = $\pi r^2$
Therefore, total surface area of cone = $\pi rl+\pi r^2$