Question

A right circular cone is $8\text{cm}$ high, the radius of the base is $6\text{cm}$. Find the curved surface area

• A. $314{\text{cm}}^2$
• B. $315{\text{cm}}^2$
  
• C. $413{\text{cm}}^2$
  
• D. $431{\text{cm}}^2$
  

Answer 1

The correct option is A $314{\text{cm}}^2$

Given:

$h=8\text{cm}$

$r=6\text{cm}$
Curved surface area $=\pi rl$
$l=\sqrt{h^2+r^2}$
$=\sqrt{8^2+6^2}$
$=\sqrt{64+36}=\sqrt{100}$
$=10\text{cm}$
$\therefore$ Curved surface area $=3.14\times 10\times 10=314{\text{cm}}^2$.