2012 · Q46
A cardboard sheet in the form of a circular sector of radius 30 cm and central angle 144 degrees is folded to make a cone. What is the radius of the cone?
Elementary MathematicsMensuration
- A12 cm
- B18 cm
- C21 cm
- DNone of the above
Explanation
Arc length (144/360)*2*pi*30 = 24*pi equals the base circumference 2*pi*r, so r = 12 cm.