1.  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

Answer: Option C

Explanation:

l = 10 m,

h = 8 m.

So, r = l2 - h2 = (10)2 - 82 = 6 m.

Curved surface area = rl = ( x 6 x 10) m2 = 60 m2.