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In a circle of radius 21 cm, an arc subtends an angle of 72° at the centre. The length of the arc is
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- 21.6 cm
- 26.4 cm
- 13.2 cm
- 19.8 cm
- 21.6 cm
Correct Option: B
Here , Rradius ( r ) = 21 cm
| θ = 72° = 72 × | radians | |
| 180 |
| θ = | radians | |
| 5 |
As we know that ,
| ∴ θ = | |
| r |
l → length of arc
| ⇒ l = θ.r = | × 21 | |
| 5 |
| l = | × | × 21 | ||
| 5 | 7 |
| l = | = 26.4 cm. | |
| 5 |
