Q8 of 45 Page 138

Two buildings are in front of each other on a road of width 15 meters. From the top of the first building, having a height of 12 meter, the angle of elevation of the top of the second building is 30°.What is the height of the second building?


Let AB and CD be two building, with


AB = 12 m


And angle of elevation from top of AB to top of CD = ∠CAP = 30°


Width of road = BD = 15 m


Clearly, ABDP is a rectangle


With


AB = PD = 12 m


BD = AP = 15 m


And APC is a right-angled triangle, In ∆APC






⇒ CP = 5√3 m


Also,


CD = CP + PD = (5√3 + 12) m


Hence, height of other building is (12 + 5√3 m).


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