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The radius and the height of a cone are in the ratio 4 : 3. The ratio of the curved surface area and total surface area of the cone is
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- 5 : 9
- 3 : 7
- 5 : 4
- 16 : 9
- 5 : 9
Correct Option: A
| = | ⇒ | = | = k | |||||
| h | 3 | 4 | 3 |
⇒ r = 4k; h = 3k
∴ l = √r² + k² = √16k² + 3k²
= √25k² = 5k
| ∴ | |
| Total surface area |
| = | |
| πr(r + l) |
| = | = | = | |||
| r + l | 4k + 5k | 9 |
or 5 : 9
