If the radius of a sphere becomes 3 times then its volume will become

Let r₁ be the initial radius of the sphere.

∴ r₁= r

Let r₂ be the radius after increasing it 3 times the size of initial radius.

∴ r₂ = 3r

Let V₁ be the initial volume of the sphere

∴ V₁ = × π × (r₁)³ = × π × r³

Let V₂ be the volume of the sphere after its radius is increased by 3 times.

∴ V₂ = × π × (r₂)³ = × π × (3r)³

⇒ V₂ = 27 × × π × r³

∴ If radius is increased by 3 times, its volume will be increased by 27 times.