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Homework Help: 104.5 degree triangle w/ 2 equal legs, need the 3rd leg's length

  1. Oct 8, 2009 #1
    1. The problem statement, all variables and given/known data

    i have a triangle with 2 legs of 96 inches. the angle between them is 104.5 degrees. how do i get the length of the 3rd leg?

    2. Relevant equationswish i knew.

    3. The attempt at a solution
    tried Cos, Sin, and Tan of 104.5 * length of a leg
  2. jcsd
  3. Oct 8, 2009 #2
  4. Oct 8, 2009 #3


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    Gold Member

    Draw a line down the centre. Now you have two right-angled triangles. It should be a piece of cake from there.
  5. Oct 8, 2009 #4
    when i tried this i got 1.17545571, but the answer should be 1.5.

  6. Oct 8, 2009 #5
    thanks man! i think this worked, and i kind of understand why.

    i still dont understand why the law of cosines didnt work for me, i wonder what i screwed up....
  7. Oct 8, 2009 #6
    you forgot one of the minus signs in -2(.96)(.96)(-.25038)
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