Question

If the radius of a cylinder is doubled and the height remains same, the volume will be

(a) doubled (b) halved

(c) same (d) four times

Answer 1

If r be the radius and h be the height, then volume = $\pi r^2$ h

If radius is doubled and height remain same,

the volume will be

=$\pi (2r{)}^{2}h=\pi \times 4r^2$ h

=$4\pi r^{2}h=4\times$ Volume

The volume is four times more than the original volume.

The correct answer is (d) four times