Question

The slant height of a right circular cone is 10 m and its height is 8 m. Find the area of its curved surface. (in $m^2$)

• A. $30\pi$
• B. $40\pi$
• C. $60\pi$
• D. $80\pi$

Answer 1

The correct option is C $60\pi$

$\text{Given, slant height,}l=10m\text{height,}h=8m\text{We know,}l=\sqrt{r^2+h^2},\text{where,}r\text{is the radius of the cone}.\text{So,}{r}^2=l^2-h^2=100-64=36⟹r=6m\text{Curved surface area}=\pi rl=\pi \times 6\times 10=60\pi m^2$