Find the area of the curved surface of a cone whose base radius is 3cm and whose height is 4cm (π = 3.14)
A
17.1cm2
B
27.2cm2
C
47.1cm2
D
37.3cm2
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
Find the slant height
\( l^2 = h^2 + r^2(h = 4cm,r = 3cm)\)
\( l^2 = 4^2 + 3^2 = 16 + 9 = 25 \)
\( l^2 = √ 25 \)
Squaring both sides
l = 5cm
The area of curved surface (s) =π(3)(5)
15π = 15 × 3.14
= 47.1cm2
Source: Myschool Past Questions Archive (Record #41283)