Question

The diameter of the base of cone is $10cm$ and its slant height is $17cm$. Then the curved surface area of the cone is ____$c{m}^2$.

• A. $85\pi$
• B. $170\pi$
• C. $95\pi$
• D. $88\pi$

Answer 1

The correct option is A $85\pi$

$\to$ Given diameter of the base of the cone is $10cm$

$\therefore$ radius $=5cm$. $(\because radius=\frac{diameter}{2})$.

Also, the slant height of the cone $=17cm$.

$\therefore$ The curved surface area of the cone is ${}^{\prime }\pi r{l}^{\prime }$.

$r:$ radius of the base.

$l:$ slant height.

$S=\pi rl=\pi \times 5\times 17=85\pi c{m}^2$.

$\therefore$ curved surface area of the cone is $85\pi c{m}^2$