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Mathematics to the Frenchmen 2 :)

Mathematics: In a triangle ABC are (BC)=2(AB) and (AC)=5/2(AB) a.) Find cos c b.) Find the area of the triangle ABC expressed by c Again good luck 😀

Posted in Group8.

2 comments

By Majea – 20 May 2009

2 Responses

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  1. chartrac says

    I imagine the triangle ABC is a right triangle, isn’t it ???

    thank you

    26 May 2009, 13:49
  2. hammamis says

    1) When we use the theoreme of Al-Kashi, we find :

    x²=(2x)²+(5/2x)²-2*2x*5)2x*cos ACB(angle)
    …
    x²=1x²/4*cos ACB
    x²/(x²/4)= cos ACB
    x²*4/x²= cos ACB
    4x²/x²= cos ACB
    4= cos ACB

    So the cosinus of c is 4.

    2)
    The formule for find the aera of a triangle is (b*h)/2
    so in this triangle is (5/2(AB)*cosC)*h/2 (but we are not sure)

    4 June 2009, 10:59

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