If the diameter of sphere is decreased by 25%,then by what % its curved surface area would decrease?

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.