Question

Diameter of the base of a cone is $10.5$ cm and its slant height is $10$ cm. Find its curved surface area.

• A. $104.85c{m}^2$
• B. $164.85c{m}^2$
• C. $100.75c{m}^2$
• D. None of these

Answer 1

Answer: (B)

$164.85c{m}^2$

Given, the diameter of base of cone $d=10.5cm$.

Then, radius of the cone $r=\frac{d}{2}=\frac{10.5}{2}=5.25cm$.

Also, slant height of cone $l=10cm$.

Then, the curved surface area $=\pi rl$

$=3.14\times 5.25\times 10=164.85c{m}^2$.

$\therefore$ Curved surface area of the given cone is $164.85c{m}^2$.

Hence, option $B$ is correct.