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प्रश्न
Prove that the surface area of a sphere is equal to the curved surface area of the circumference cylinder__?
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उत्तर
Let radius of a sphere be r
Curved surface area of sphere = 4πr2
S1 = 4πr2
Let radius of cylinder be 'r 'cm
Height of cylinder be '2' r cm
Curved surface area of cylinder = 2πrh
S2 = 2πr(2r) = 4πr2
S1 and S2 are equal. Hence proved
So curved surface area of sphere = surface area of cylinder
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