A hemispherical bowl made of brass has inner diameter 10.5 cm. Find the cost of tin-plating it on the inside at the rate of Rs 16 per 100 cm2
Inner radius (r) = 
= 5.25 cm
Surface area of hemispherical bowl = 2πr2
= 2 * 
* 5.25 * 5.25
= 173.25 cm2
Cost of tin-plating 100 cm2 area = Rs 16
Cost of tin-plating 173.25 cm2 area = (
)
= Rs 27.72
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