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Angle ABC (Posted on 2006-02-25) Difficulty: 3 of 5
In a triangle ABC, D is the midpoint of BC. Join AD. Angle ADB = 45 degree and angle ACB = 30 degree. Find angle ABC.

No Solution Yet Submitted by akash    
Rating: 2.3000 (10 votes)

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Solution alternative aproach | Comment 8 of 17 |

let AH be a perpendicular line (H belongs to BC)

In the AHC triangle we have AH=AC * 1/2  and HC=AC*(¡î3)/2

HC=AH*¡î3

In the ADH trinangle we have DH=AH

DH+HC=a (a=BC/2) (AH=h)

tg(ABC)=AH/BH = h/a+h = h/h(2+¡î3) ==>

(ABC)=arctg (1/2+¡î3) .......ABC = 105¨¬


  Posted by vije on 2006-02-26 11:24:11
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