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From the top of a lighthouse, 50 m above the sea, the angle of depression of an incoming boat is 30°. How far is the boat from the lighthouse?
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- 25 √3 m
- 25 / √3 m
- 50 √3 m
- 50 / √3 m
Correct Option: C
From given figure , we have
TL = 50 m , θ = 30°
In triangle TBL ,
| tan30° | = | TL | ⇒ | 1 | = | 50 |
| BL | √3 | BL |
∴ BL = 50 √3 m.
The boat from the lighthouse far is 50 √3 m.
