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The angle of elevation of a hovering helicopter as seen from a point 45 m above a lake is 30c and the angle of depression of its reflection in the lake, as seen from the same point and at the same time, is 60c. Find the distance of the helicopter from the surface

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4 years ago

Faiz
107 Points
```							Let the point 45 m above the lake surface from which you are seeing the helicopter be A.... Let the parallel component of distance btw helicopter and A be p m... Let that point ke D....AD=p m... If helicopter us at h m above the lake surface then its reflection will be h m inside the lake... Let helicopter be at H... And its reflected image be H`... Now tan 30° = (h-45)/p.... And tan 60° = (h+45)/p... Solving these two you can find h....taje out p from second eq. and sustitute in the first...ans::::: 90 metres.
```
4 years ago
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### Course Features

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### Course Features

• 31 Video Lectures
• Revision Notes
• Test paper with Video Solution
• Mind Map
• Study Planner
• NCERT Solutions
• Discussion Forum
• Previous Year Exam Questions