NumericalHard3 marks
Two lamp posts AB and CD each of height 100 m are on either side of the road. P is a point on the road between the two lamp posts. The angles of elevation of the top of the lamp posts from the point P are 60°and 30°. Find the distances PB and PD.
Topic: Heights and distances
Previous-year question practice database
Answer
Solution diagram
Exam answer
PB = 100/√3 m ≈ 57.7 m; PD = 100√3 m ≈ 173.2 m.
Explanation
Using tan 60° = 100/PB and tan 30° = 100/PD.
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