Mathematics

A cone is made from a sector of circle of radius 14cm and angle of…

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)
  • A.
    22cm2
  • B.
    38.5cm2
  • C.
    77cm2
  • D.
    154cm2
  • E.
    308cm2
Correct Answer: Option D
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