Question

The radius of the base of a right circular cylinder is halved and the height is double. What is the ratio of the volume of the new cylinder to that of that of the original cylinder? ​

Answer 1

let the radius of cylinder = (r) units

let height of cylinder = (h) units

thus volume of cylinder , v'= πr²2h cubic units

if radius is halved then

new radius = r/2

new height = 2h

new volume = v

volume = π(r/2)²(2h)

πr^2h =1/4(πr²2h)

v' =1/4 v

v'/v=1/4

the ratio is 1:4