Q2 of 75 Page 225

Find the surface area of a sphere of diameter:

(i) 14 cm


(ii) 21 cm


(iii) 3.5 m

(i) Radius (r) of sphere =

=


= 7 cm


Surface area of sphere = 4r2


= 4 * * 7 * 7


= 88 * 7


= 616 cm2


(ii) Radius (r) of sphere =


=


= 10.5 cm


Surface area of sphere = 4r2


= 4 * * 10.5 * 10.5


= 1386 cm2


(iii) Radius (r) of sphere =


=


= 1.75m


Surface area of sphere = 4r2


= 4 * * 1.75 * 1.75


= 38.5 cm2


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