A cone is made from a sector of circle of radius 14cm and angle of 90o. What is the area of the curved surface of the cone? (Take x = 22/7)
- 22cm2
- 38.5cm2
- 77cm2
-
154cm2
- 308cm2
The correct answer is: D
Explanation
Length of arc =
ฮธ360
* 2ฯr=> r =
90360
* 144
= 3.5 slant height t = 14cm
curved surface area of cone = ฯrl
=> 3.142 x 3.5 x 14 = 153.95