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The amount of concrete required to build a concrete cylindrical pillar whose base has a perimeter 8.8 metre and curved surface area 17.6 square metre, is (Take π = 22/7)
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- 8.325 m³
- 9.725 m³
- 10.5 m³
- 12.32 m³
- 8.325 m³
Correct Option: D
Radius of the base of cylindrical pillar = r metre (let)
∴ 2πr = 8.8
| ⇒ 2 × | × r = 8.8 | |
| 7 |
| ⇒ r = | = 1.4 metre | |
| 2 × 22 |
Again,
2πrh = 17.6
⇒ 8.8 × h = 17.6
| ⇒ h = | = 2 metre | |
| 8.8 |
∴ Volume of concrete = πr²h
| = |  | × 1.4 × 1.4 × 2 |  | cu.cm. | |
| 7 |
= 12.32 cu. metre
