SOLUTION: The internal and external diameters of a hollow sphere are 20cm and 28cm respectively find the cost of painting all over the hollow hemisphere at 14paise per square cm

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Question 977266: The internal and external diameters of a hollow sphere are 20cm and 28cm respectively find the cost of painting all over the hollow hemisphere at 14paise per square cm

Answer by Alan3354(69443) About Me  (Show Source):
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The internal and external diameters of a hollow sphere are 20cm and 28cm respectively find the cost of painting all over the hollow hemisphere at 14paise per square cm
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SA+=+pi%2Ad%5E2
There are 2 surfaces, the inside and the outside
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Total SA = pi%2A20%5E2+%2B+pi%2A28%5E2 sq cms for a sphere
The hemisphere's SA ia 1/2 that.
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Multiply the cost/sq cm by the SA