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The length of canvas, 75 cm wide required to build a conical tent of height 14m and the floor area 346.5 m² is
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- 665 m
- 860 m
- 490 m
- 770 m
- 665 m
Correct Option: D
Area of the base of conical tent = 346.5 sq. metre
∴ πr² = 346.5
| ⇒ | × r² = 346.5 | |
| 7 |
| ⇒ r² = | = 110.25 | |
| 22 |
⇒ r = √110.25 = 10.5 metre
∴ Slant height = √h² + r²
= √(14)² + (10.5)² = √196 + 110.25
= √306.25 = 17.5 metre
∴ Area of curved surface of the tent = πrl
| = | × 10.5 × 17.5 | |
| 7 |
= 577.5 sq. metre
| ∴ Length of canvas = | = | |||
| 75 | ||||
| 100 | ||||
| = | = 770 metre | |
| 75 |
