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Math Help - Find Length a

  1. #1
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    Find Length a

    In ΔABC, sin A = 1/4, sin B = 1/8, and b = 20. What is the length of a?

    Do I apply the law of sines here?
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  2. #2
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    Try the law of sines.

    \frac{sinA}{a}=\frac{sinB}{b}

    a=\frac{bsinA}{sinB}

    The law of cosines is used when we have angle, side, angle. Like in the diagram:
    Attached Thumbnails Attached Thumbnails Find Length a-law-cosines.gif  
    Last edited by galactus; January 4th 2009 at 02:27 PM. Reason: include diagram
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  3. #3
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    ok.........

    Quote Originally Posted by galactus View Post
    Try the law of sines.

    \frac{sinA}{a}=\frac{sinB}{b}

    a=\frac{bsinA}{sinB}

    The law of cosines is used when we have angle, side, angle. Like in the diagram:
    I knew it. Thanks!
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