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Some Applications Of Trigonometry

Question
CBSEENMA10009747

Two poles of equal heights are standing opposite each other on either sideof the roads, which is 80 m wide. From a point between them on theroad, the angles of elevation of the top of the poles are 60o and 30orespectively. Find the height of the poles and the distances of the pointfrom the poles.

Solution

Let  AC and  BD  be the two poles of the same height  h m.Given: AB = 80 mLet AP = x m, therefore, PB= (80 - x ) mIn APC,tan 30° = ACAP13 = hx        .........(1)In BPD,tan 60° = BDAB3 =h80-x       .............(2)Dividing (1) by (2),133 = hx  h80-x13 = 80-xxx = 240 - 3x 4x = 240 x = 60From (1),13 = hxh = 603 = 203 mThus, the height of both the poles is  203 m and the distance of the point fromthe poles are  60 m and  20 m.