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The curved surface area and the total surface area of a cylinder are in the ratio 1 : 2. If the total surface area of the right cylinder is 616 cm², then its volume is :
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- 1232 cm³
- 1848 cm³
- 1632 cm³
- 1078 cm³
- 1232 cm³
Correct Option: D
2πrh : 2πrh + 2πr&up2;= 1 : 2
⇒ 2πrh : 616 = 1 : 2
| ⇒ 2πrh = | = 308 | |
| 2 |
∴ 2πrh + 2πr² = 616
→ 308 + 2πr² = 616
⇒ 2πr² = 308
| ⇒ r² = | = 49 | |
| 22 × 2 |
⇒ r = 7
| ∴ 2 × | × 7 × h = 308 | |
| 2 |
| ⇒ h = | = 7 | |
| 44 |
∴ Volume of cylinder = πr²h
