Question

If the radius of a sphere is doubled what happens to the volume

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