Same chapter4 marksDifficulty: Hard
An aeroplane flying horizontally at a height of 3000 m is observed at an angle of elevation of 60°. After 15 seconds the angle is 30°. Find the speed of the aeroplane in km/h.
Heights and Distances
4 marksDifficulty: Hard
The angles of elevation of the top of a tower from two points on the same side of it and in line with its foot are 30° and 60°. If the points are 40 m apart, find the height of the tower.
Original Khojo Papers practice question — not from a past board paper.
Answer
20√3 ≈ 34.64 m
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
If the height is h then the distances of the two points are h/tan 30° = h√3 and h/tan 60° = h/√3. Their difference is 40, so h√3 − h/√3 = 40, that is 2h/√3 = 40 and h = 20√3 m.
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From the same topic and chapter, at a similar level.
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Heights and Distances