# The suraface area of a solid sphere is increased by 21% with out changing its shape.find % change in radius and volume

1
by arun71

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by arun71

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A1/A2 = (r1/r2)2

1.21A1/A1 = (r2/r1)2

1.1 = r2/r1

∴ r2 = 1.1r1

∴ Increase percentage = (r2 – r1) / (r1) x 100 % = (1.1r1 – r1)/ (r1) x 100 % = 10

V1/V2 = (r1/r2)3

V2/V1 = (11/10)3

= 1.331

∴ V2 = 1.331 V1

Increase % = (V2 – V1) / (V1) x 100 % = (1.331 V1 – V1) / V1 x 100 %

= 33.1%