Q17 of 48 Page 13

The diameter of a sphere is decreased by 25%. By what percent does its curved surface area decrease?

Concept Used: Curved Surface Area of Sphere = 4πr2


Radius


Given: Diameter of the Sphere is decreased by 25%


Assumption:


Let r1 be the initial radius, r2 be the increased radius


Explanation:


Radius (r1)


New radius (r2)



Initial Surface Area = CSA (S1) = 4πr12



= πd2


Decreased Surface Area = CSA (S2) = 4πr22




Decrease in surface area = S1 – S2




Now,


Percentage decrease




= 43.75 %


Hence, the decrease in surface area is 43.75%.


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