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

Explanation

let radius `=r`

and height `=h`

so volume `v=pixx(r^2)h`

in new case radius `R=2r`

height `h=h`
so new volume `V=pixx(2r)^2(h)`

`=4xx[pixx(r^2)h]`

`=4v`
so ans is d) four times