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A B is a vertical pole with B at the ground level and A at the top. A man finds that the angle of elevation of the point A from a certain point C on the ground is 60^ . He moves away from the pole along the line B C to a point D such that C D=7 ~m . From D the angle of elevation of the point A is 45^ . Then the height of the pole is

Options

  1. A7 3 2 1 3 -1 m
  2. B7 3 2 ( 3 +1) m
  3. C7 3 2 ( 3 -1) m
  4. D7 3 2 1 3 +1

Correct answer

B. 7 3 2 ( 3 +1) m

Step-by-step solution

aligned & BD = AB =7+x & Also AB = x 60^ =x 3 & x 3 =7+x & x = 7 3 -1 & AB = 7 3 2 ( 3 +1) aligned

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