Q18 of 227 Page 917

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.

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