Height of a tower from two angles of elevation measured on a straight line away from its base

Height of a tower from two angles of elevation measured on a straight line away from its base

IB Year 6 | Grade 12
6 marks

A vertical radio mast \(FT\) stands on horizontal ground, with its foot at \(F\) and its top at \(T\). The height of the mast is \(h\) metres.

A surveyor stands at the point \(P\), where \(PF=x\) metres, and measures the angle of elevation of \(T\) as \(52^\circ\). She then walks \(45\) metres directly away from the mast to the point \(Q\), where the angle of elevation of \(T\) is \(24^\circ\). The points \(Q\), \(P\) and \(F\) lie on a straight line.

  1. Express each of the following in terms of \(h\) and \(x\).[2]
    1. \(\tan52^\circ\)
    2. \(\tan24^\circ\)
  2. Hence find \(x\).[2]
  3. Find \(h\).[2]

Solution:

Solution locked

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Answer:(a)(i) \(\dfrac{h}{x}\) (a)(ii) \(\dfrac{h}{x+45}\) (b) \(x=24.0\text{ m}\) (c) \(h=30.7\text{ m}\)

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