Q23 of 50 Page 1

From the top of a 60m high building, the angles of depression of the top and the bottom of a tower are 45° and 60° respectively. Find the height of the tower.


Let height of the building be BD = 60 m


The height of the tower is ‘h’. The distance between the base of the building and the tower be ‘d’.


In Δ ADE,


⇒ tan 60°


⇒


⇒ d


∴ BC = 20√3 = 20 (1.73) = 34.60 m


In Δ ABC,


⇒ tan 45°


⇒ 1


∴ AC = 34.60 m


∴ Height of tower = AE – AC = 60 – 34.60 = 25.4 m


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