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An arc of 30° in one circle is double an arc in a second circle, the radius of which is three times the radius of the first. Then the angles subtended by the arc of the second circle at its centre is
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- 3°
- 4°
- 5°
- 6°
- 3°
Correct Option: C
According to question , we draw a figure of a circle with radius r , 
| θ = | ; | = 2 ; | = 3 | |||
| r | l2 | l1 |
| ∴ | = | = 2 × 3 = 6 | ||
| θ2 | l2r1 |
| ⇒ | = 6 | |
| θ2 |
| ⇒ θ2 = | = 5° | |
| 6 |
 | θ (radian) = | . Here, | is a ratio. |  | ||
| r | θ2 |
