Saved Bookmarks
| 1. |
Find the surface area of a sphere of diameter: (i) 14 cm (ii) 21 cm (iii) 3.5 cm |
|
Answer» Surface area of a sphere = 4πr2 Where, r = radius of a sphere (i) Diameter = 14 cm So, Radius = \(\frac{Diameter}{2}\) = \(\frac{14}{2}\) cm = 7 cm Surface area = 4 x \(\frac{22}{7}\) x (7)2 = 616 Surface area is 616 cm2 (ii) Diameter = 21 cm So, Radius = \(\frac{Diameter}{2}\) = \(\frac{21}{2}\) cm = 10.5 cm Surface area = 4 x \(\frac{22}{7}\) x (10.5)2 = 1386 Surface area is 1386 cm2 (iii) Diameter= 3.5 cm So, Radius = \(\frac{Diameter}{2}\) = \(\frac{3.5}{2}\) cm = 1.75 cm Surface area = 4 x \(\frac{22}{7}\) x (1.75)2 = 38.5 Surface area is 38.5 cm2 |
|