Mathematics

The angle of a sector of a circle of radius 8cm is 240°. This sector…

The angle of a sector of a circle of radius 8cm is 240°. This sector is bent to form a cone. Find the radius of the base of the cone.

  • A.
    16/3cm
  • B.
    15/3cm
  • C.
    16/5cm
  • D.
    8/3cm
  • E.
    16/10cm
Correct Answer: Option A
Explanation

L = θ/360 x 2πR = 240/360 x 2 x 22/7 x 8/1 … (1)

This must be equal to the circumference of the circle which is 2πr = 44R/7 …. (2)

equate (1) and (2)

r = 16/3 = 51/3