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Math Help - triangle trig

  1. #1
    Junior Member
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    Sep 2008
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    triangle trig

    A triangle has a 56-degree angle, formed by a 10-inch side and an x-inch side. Given that the area of the triangle is 18 square inches, find x.
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  2. #2
    Super Member
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    Jun 2008
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    One of the formulas for the area of a triangle is given by:

    A = \frac{1}{2}ab\sin{C}

    Where C is an angle and a and b are the sides of the angle.
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  3. #3
    MHF Contributor
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    Use the law of cosines to find the length of the third side in terms of x. Then apply Heron's Formula: A = \sqrt{s(s - a)(s - b)(s - c)}

    where A is the area, s is half of the perimeter, and a, b, and c are the sides. Edit: Chop Suey's method is much easier.
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