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    Question

    Two Poles are 12 metres apart horizontally and the

    height of one is double that of the other. If from the mid-point of the line joining their feet, an observer finds the angular elevations of their tops to be complementary. Then the height of the shorter post is:
    A 2m Correct Answer Incorrect Answer
    B 3√2m Correct Answer Incorrect Answer
    C 3m Correct Answer Incorrect Answer
    D 2√2m Correct Answer Incorrect Answer

    Solution

    Let AB = taller pole CD = shorter pole = h OB = OD =( 12)/2 = 6m In ∆OCD, tanθ = h/6 ............................(i) In ∆AOB tan⁡ (90- θ) = 2h/6 = h/3 cotθ= h/3 .............................(ii) Multiplying (i) and (ii), we get tanθ × cotθ = h/6 × 4/3 1 = h²/18 h² = 18 h=3√2 m

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