Mathematics for IGCSE & O level - Mensuration (Section 14 - No. 6)

If the radius of a sphere is increased by a factor of 3, by what factor does the volume increase?

Volume = 4/3 * π * r³. If r becomes 3r, the volume becomes 4/3 * π * (3r)³ = 27 * (4/3πr³) so the volume is multiplied by 27.