farhan.k , asked a question
Subject: Math , asked on 22/2/11

 At a point on level ground, the angle of elevation of a vertical   tower is found to be such 
that its tangent is 5/12.
 On walking 192m towards the tower, the tangent of the angle of  .
elevation is  3/4.
         
 .Find the height of the tower.                             

Devanshi Modha , added an answer, on 22/2/11
48 helpful votes in Math

 

let height of the tower b h

 tan theta = 5/12

h /192 + x = 5/12

12h = 5(192 + x)

12h = 960 + 5x

x = -960 + 12h/5  __ 1

tan phi = h/x

3/4 = h/x

x = 4h / 3._____2

1 = 2

-960+12h/5 = 4h/3

3(-960 + 12h) = 20h

-2880 + 36h = 20h

2880 = 16h

Therefore h = 2880 / 16 =  180 m

 

 

 

 

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