Question

the radius of a sphere is doubled . find the increase percent in its surface area

Answer 1

Let the radius be r

Now the surface area = 4π(r) ² = 4πr²

The radius of the sphere is doubled.

The radius = 2r.

Now the surface area = 4π(2r)² = 16πr² .

Increase % in area = 16πr²-4πr²/4πr² * 100 = 12/4*100 = 300% .

Answer 2

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