2. Find the surface area of a sphere of diameter: (i) 14 cm (ii) 21 cm (iii) 3.5 m

(i) Diameter (d) = 14 cm 14 Radius (r) = = 7 cm Now, surface area of the sphere = 4xr2 192 = 4 x 22 7 x 7 x 7 = 4 x .22 x 7 = 616cm2. (ii) Diameter (cl) = 21 cm :. Radius (r) = 21 cm 2 Now, surface area of the sphere = 4nr2 22 21 21 = 4 x x x = 1386 cm (iii) Diameter (d) = 3.5 m . 3.5 7 :. Radius (r) m = m Now, surface area of the sphere = 4nr2 22 7 7 22x 7 2 = 4 x 7 x 4 x 4 = 4- = 38.5 m •