There are two buildings, one on each bank of a river, opposite to each other. From the top of one building – 60 m high, the angles of depression of the top and the foot of the other building are 30° and 60° respectively. What is the height of the other building?
Explanation:
Let the height of the shorter building be h.
Let the distance between the two buildings be x.
Therefore from the diagram,
tan 60 = 60x
∴ x = 603 = 203
∴ tan 30 = 60-hx
∴ 60 - h = 20
∴ h = 40
Hence, option (c).
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