Question

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

• A. $165{cm}^2$
• B. $135{cm}^2$
• C. $265{cm}^2$
• D. $164{cm}^2$

Answer 1

Answer: (A)

$165{cm}^2$

$\because$ Diameter of the base $=10.5cm$
$\therefore$ Radius of the base $\left(r\right)=\frac{10.5}{2}cm=5.25cm$
Slant height $\left(l\right)=10cm$
$\therefore$ Curved surface area of the cone
$=\pi rl=\frac{22}{7}\times 5.25\times 10=165{cm}^2$