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IS 60°. Find the length of the string, assug. The angle ofAl boy is standing at some distance from a 30 m tall building. Thealelevationfrom his eyes to the top of the building increases from 30° to 60° as hed the distance he walked towards the building |
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Answer» Let AB=CD= EQ = 1.5 mLet dist. covered by boy is BD=xLet BD=AC=xLet DQ=CE=yIn fig. PE=30-1.5=28.5mAngles are 30° and 60°In ∆ PAE tan 30 = PE/AE1/√3=28.5/x+y 28.5√3=x+y –(1) In ∆PCEtan60=PE/CE√3=28.5/yy=28.5/√3 Put in (1)x+28.5/√3=28.5√4x=(28.5×3-28.5)/√3= (85.5-28.5)/√3=57/√3 Rationalize=57/√3×√3/√3=57√3/3=19√3 |
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