Question

If the radius of the sphere is doubled, Find the ratio of volume of the new sphere to the original sphere.

Answer 1

let the original radius be r

so the original volume = 4/3πr³

new radius = 2r

so new volume = 4/3π (2r)³ = 4/3 π (8r³)

ratio = 4/3πr³/4/3π (8r³)
        = r³ / 8r³ = 1/8 

so the ratio is 1:8

Answer 2

let the original radius be r
so the original volume4/3Tr
new radius 2r
(2r)34/3 TT (8r5)
SOnew volume e4/3
ratio b4/3T /4/3T (8r)
- r3 /8rs1/8
so the ratio is 1:8