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प्रश्न
Find the surface area of a sphere of diameter 3.5 cm.
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उत्तर
Diameter = 3.5cm
Radius = `(3. 5cm)/2 -1.75 cm.`
∴ Surface area = `4πr^2 - 4 × 22/7 × (3.5)/(2^2)`
= 38.5 cm 2
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