Question

Find the surface area of a sphere of radius:
(i) 10.5 cm
(ii) 5.6 cm
(iii) 14 cm

Answer 1

(i) Radius (r) of sphere = 10.5 cm
Surface area of sphere = $4\pi r^2$
= 4 × $\frac{22}{7}$ × (10.5cm)2
= 1386 cm2
Therefore, the surface area of a sphere having radius 10.5cm is 1386 cm2 .

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(ii) Radius(r) of sphere = 5.6 cm
Surface area of sphere = $4\pi r^2$
= 4 × $\frac{22}{7}$× (5.6cm)2
= 394.24 cm2
Therefore, the surface area of a sphere having radius 5.6 cm is 394.24 cm2 .

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(iii) Radius (r) of sphere = 14 cm
Surface area of sphere =$4\pi r^2$
= 4 × $\frac{22}{7}$ × (14cm)2
= 2464 cm2
Therefore, the surface area of a sphere having radius 14 cm is 2464 cm2 .