A cone is made from a sector of a circle of radius 14cm and angle of 90o. What is the area of the curved surface of the cone? (Take x = 22/7)

A. 22cm2
B. 38.5cm2
C. 77cm2
D. 154cm2
E. 308cm2

Correct Answer: Option D

D. 154cm2

Explanation
Length of arc =
θ/360
* 2πr

=> r =
90/360
*
14/4
= 3.5

slant height t = 14cm
curved surface area of cone = πrl
=> 3.142 x 3.5 x 14 = 153.95