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28/07/2021 10:31 am
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Find the surface area of a sphere of diameter:
(i) 14 cm (ii) 21 cm (iii) 3.5 cm
(Assume π = 22/7)
1 Answer
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28/07/2021 10:32 am
(i) Radius of sphere, r = diameter/2
= 14/2 cm = 7 cm
Formula for Surface area of sphere = 4πr2
= 4 × (22/7) × 72 = 616
Surface area of a sphere is 616 cm2
(ii) Radius (r) of sphere = 21/2
= 10.5 cm
Surface area of sphere = 4πr2
= 4 × (22/7) × 10.52 = 1386
Surface area of a sphere is 1386 cm2
Therefore, the surface area of a sphere having diameter 21 cm is 1386 cm2
(iii) Radius(r) of sphere = 3.5/2
= 1.75 cm
Surface area of sphere = 4πr2
= 4 × (22/7) × 1.752 = 38.5
Surface area of a sphere is 38.5 cm2