1. Radius of sphere r = 14/2 = 7 cm Surface area of sphere = 4πr² = 4 × 22/7 × 7 × 7 = 4 × 22 × 7 = 616 cm² Hence, the surface area of sphere is 616 cm².

    Radius of sphere r = 14/2 = 7 cm
    Surface area of sphere = 4πr²
    = 4 × 22/7 × 7 × 7 = 4 × 22 × 7 = 616 cm²
    Hence, the surface area of sphere is 616 cm².

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  2. Radius of sphere r = 5.6 cm Surface area of sphere = 4πr² = 4 × 22/7 × 5.6 × 5.6 = 4 × 22 × 0.8 × 5.6 = 394.24 cm² Hence, the surface area of sphere is 394.24 cm².

    Radius of sphere r = 5.6 cm
    Surface area of sphere = 4πr²
    = 4 × 22/7 × 5.6 × 5.6 = 4 × 22 × 0.8 × 5.6 = 394.24 cm²
    Hence, the surface area of sphere is 394.24 cm².

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  3. Radius of sphere r = 21/2 = 10.5 cm Surface area of sphere = 4πr² = 4 × 22/7 × 10.5 × 10.5 = 4 × 22 × 4.5 × 10.5 = 1386 cm² Hence, the surface area of sphere is 1386 cm².

    Radius of sphere r = 21/2 = 10.5 cm
    Surface area of sphere = 4πr²
    = 4 × 22/7 × 10.5 × 10.5 = 4 × 22 × 4.5 × 10.5 = 1386 cm²
    Hence, the surface area of sphere is 1386 cm².

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  4. Radius of sphere r = 3.5/2 = 1.75 cm Surface area of sphere = 4πr² = 4 × 22/7 × 1.75 × 1.75 = 4 × 22 × 0.25 × 1.75 = 38.50 cm² Hence, the surface area of sphere is 38.5 cm².

    Radius of sphere r = 3.5/2 = 1.75 cm
    Surface area of sphere = 4πr²
    = 4 × 22/7 × 1.75 × 1.75 = 4 × 22 × 0.25 × 1.75
    = 38.50 cm²
    Hence, the surface area of sphere is 38.5 cm².

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  5. Internal radius of hemispherical bowl r = 10.5/2 = 5.25 cm Inner surface area of hemispherical bowl = 2πr² = 2 × 22/7 × 5.25 × 5.25 = 2 × 22 × 0.75 × 5.25 = 173.25 cm² Cost of tin-plating the rate of Rs 16 per 100 cm² = Rs 173. 25 × 16/100 = Rs 27.72 Hence, the cost of tin- plating inside at the ratRead more

    Internal radius of hemispherical bowl r = 10.5/2 = 5.25 cm
    Inner surface area of hemispherical bowl = 2πr²
    = 2 × 22/7 × 5.25 × 5.25
    = 2 × 22 × 0.75 × 5.25
    = 173.25 cm²
    Cost of tin-plating the rate of Rs 16 per 100 cm²
    = Rs 173. 25 × 16/100 = Rs 27.72
    Hence, the cost of tin- plating inside at the rate of Rs 16 per 100 cm² is Rs 27.72.

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