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 .