From a window 2 m above the ground, the angle of depression of the foot of a tower is 30° and the angle of elevation of its top is 45°. What is the height of the tower?
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Hint
First find the distance from the angle of depression, then use the angle of elevation.
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Answer: B. (2 + 2√3) m
Distance to the tower: l = h cot β = 2 cot 30° = 2√3 m. Height: H = h + l tan α = 2 + 2√3 × tan 45° = (2 + 2√3) m, about 5.46 m.