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Answer:
(a) 38.3 m horizontal distance
(b) 82.1 m high
Explanation:
I like a graphical solution to this problem (attached).
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If you define h as the horizontal distance to the tower, and t as its height, you can write two equations. Since these sides are adjacent and opposite the given angles, the tangent relationship is useful.
tan(65°) = t/h
tan(40°) = (t -50)/h
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Multiplying both equations by h and substituting for t, we have ...
h·tan(40°) = h·tan(65°) -50
h = 50/(tan(65°) -tan(40°)) . . . . solve for h
h ≈ 38.3022
Then the tower height is ...
t = h·tan(65°) ≈ 82.1394
The tower is about 38.3 m distant and 82.1 m high.