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Math Help - Law of Cosines - Solve This Triangle

  1. #1
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    [SOLVED]Law of Cosines - Solve This Triangle

    Law of cosines problem:

    "Use the Law of Cosines to solve the triangle."
    ...............C
    ............./..|
    .........../....|
    5.4 yd /......|4.2 yd
    ......../.......|
    ......./.......|
    .....A------B
    ......2.1 yd

    So,
    M<A=
    M<B=
    M<C=
    a=4.2 yd
    b=5.4 yd
    c=2.1 yd

    I never wind up with the correct angle degrees. In the back of my book, it seems like the answers are always off of what I have calculated. Does anyone know how this might have happened?

    For M<A, I got 45.41 degrees. Hopefully that is the right answer.

    Thanks for any help in advance.
    -Alex
    Last edited by alexthesauceboss; January 21st 2013 at 10:48 AM. Reason: Solved
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  2. #2
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    Re: Law of Cosines - Solve This Triangle

    I made calculations for angle A by using the cosine formula that is Cos A = (b^2+c^2-a^2)/2bc and the value I got is 45.38 degrees. Little variation in such questions should be acceptable for approximations / rounding off.
    Thanks from alexthesauceboss
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  3. #3
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    Re: Law of Cosines - Solve This Triangle

    Quote Originally Posted by ibdutt View Post
    I made calculations for angle A by using the cosine formula that is Cos A = (b^2+c^2-a^2)/2bc and the value I got is 45.38 degrees. Little variation in such questions should be acceptable for approximations / rounding off.
    thanks.
    Last edited by alexthesauceboss; January 21st 2013 at 10:15 AM.
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