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Homework Help: Area of quadrilateral knowing 3 sides and 2 angles

  1. Feb 13, 2010 #1
    1. The problem statement, all variables and given/known data
    Is there an equation in which I can find the area of a quadrilateral when I know the length of three of the sides and 2 of the angles? Also I really need to find the measurement of the other two angles.

    2. Relevant equations I know the cos and sin formulas of triangles, and may be I can use that but I do not know how to start

    The lengths I know are 15, 12 & 2 and the angles I know are 120 degrees between the 12 and 2 and 120 degrees between the 15 and the side I don't know.

    3. The attempt at a solution

    I really need a nudge to start.. this is a small portion of a much bigger problem.
  2. jcsd
  3. Feb 13, 2010 #2
    Draw a picture. Find the area of the bottom trapezoid and top triangle then add them.
  4. Feb 13, 2010 #3
    OK, let me try that. I never thought of a trapezoid. Thanks.
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