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The diameter of two hollow spheres made from the same metal sheet are 21 cm and 17.5 cm respectively. The ratio of the area of metal sheets required for making the two spheres is
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- 6 : 5
- 36 : 25
- 3 : 2
- 18 : 25
- 6 : 5
Correct Option: B
| Let r1 = | cm. and | |
| 2 |
| r2 = | cm. | |
| 2 |
| ∴ Required ratio = | = | ||
| 4πr2² | r2² |
| ⇒ |  |  | ² | ||
| 2 | = | = 36 : 25 | |||
| | ² | 17.5 × 17.5 | ||
| 2 | |||||
