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CBSE Class 10 Answered

If the diameter of sphere is decreased by 25%,then by what % its curved surface area would decrease?
Asked by jishnu1994 | 25 Dec, 2009, 11:15: PM
answered-by-expert Expert Answer

CSA of a sphere = 4πR2 = πD2

Since CSA is directed propotional to the square of diameter, if we decrease the diameter by 25% i.e. make it's value 75% of the initial value,

New CSA (0.75D)2 = 0.5625D2

Hence new CSA = 0.5625 times initial CSA.

So there is a decrease of 1 - 0.5625 = 0.4375 i.e. 43.75%

Regards,

Team,

TopperLearning.

Answered by | 25 Dec, 2009, 11:59: PM
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