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.

• A. 30 m²
• B. 40 m²
• C. 60 m²
• D. 80 m²
• E. 89 m²

Answer 1

The correct option is C

60 m²

l = 10 m, h = 8 m. So, $r=\sqrt{l^2-h^2}=\sqrt{{\left(10\right)}^2-8^2}=6m$

$\therefore$Curved surface area = $\pi$rl = ($\pi$$\times$6$\times$10) m${}^2$ = 60$\pi$ m${}^2$