The slant height of a right circular cone is 10 m and its height is 8 m. Find the area of its curved surface.  Choose the correct choice from the following answers
A) 30 pi m ^ 2	B) 40 pi m ^ 2	C) 60 pi m ^ 2	D) 80 pi m ^ 2	E) 100 pi m ^ 2

Rationale: l = 10 m h = 8 m r = root ( i ^ 2 - h ^ 2 ) = root ( 10 ^ 2 - 8 ^ 2 ) = 6 m curved surface area = pi ri = 60 pi m ^ 2 answer c
Answer: C