JAMB - Mathematics (2001 - No. 14)
A sector of a circle of radius 7.2cm which subtends an angle of 300° at the centre is used to form a cone. What is the radius of the base of the cone?
8cm
6cm
9cm
7cm
คำอธิบาย
(r/L) = (θ/360°)
Given θ = 300, and L = 7.2cm,
=> r = (300 x 7.2)/360
r = 6cm
Given θ = 300, and L = 7.2cm,
=> r = (300 x 7.2)/360
r = 6cm