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
= \(4 {\pi} {r}^2\)
= [\(4 × \frac{22}{7} × (10.5)^2\) \({cm}^2\)]
= [\(4 × \frac{22}{7} × 10.5 × 10.5\) \({cm}^2\)]
= (88 × 1.5 × 10.5) \({cm}^2\)
= 1386 \({cm}^2\)

Therefore, the surface area of a sphere having radius 10.5cm is 1386 \({cm}^2\).


ii) Radius (r) of sphere = 5.6 cm
Surface area of sphere
= \(4 {\pi} {r}^2\)
= [\(4 × \frac{22}{7} × (5.6)^2\) \({cm}^2\)]
= [\(4 × \frac{22}{7} × 5.6 × 5.6\) \({cm}^2\)]
= (88 × 0.8 × 5.6) \({cm}^2\)
= 394.24 \({cm}^2\)

Therefore, the surface area of a sphere having radius 5.6 cm is 394.24 \({cm}^2\).


iii) Radius (r) of sphere = 14 cm
Surface area of sphere
= \(4 {\pi} {r}^2\)
= [\(4 × \frac{22}{7} × (14)^2\) \({cm}^2\)]
= [\(4 × \frac{22}{7} × 14 × 14\) \({cm}^2\)]
= (4 × 44 × 14) \({cm}^2\)
= 2464 \({cm}^2\)

Therefore, the surface area of a sphere having radius 14 cm is 2464 \({cm}^2\).