Q1 of 75 Page 225

Find the surface area of a sphere of radius:

(i) 10.5 cm (ii) 5.6 cm


(iii) 14 cm

(i) Radius (r) of sphere = 10.5 cm

Surface area of sphere = 4πr2


= 4 * * 10.5 * 10.5


= 88 * 1.5 * 10.5


= 1386 cm2


(ii) Radius(r) of sphere = 5.6 cm


Surface area of sphere = 4πr2


= 4 * * 5.6 * 5.6


= 88 * 0.8 * 5.6


= 394.24 cm2


(iii) Radius (r) of sphere = 14 cm


Surface area of sphere = 4πr2


= 4 * * 14 * 14


= 4 * 44 * 14


= 2464 cm2


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