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Math Help - Area of a Triangle.

  1. #1
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    Area of a Triangle.

    https://8842006143235788137-a-180274...attredirects=0

    I don't know where to start. Some of my friends told me that I need an Angle!
    Any advice?
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  2. #2
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    Re: Area of a Triangle.

    Quote Originally Posted by kreshnik View Post
    https://8842006143235788137-a-180274...attredirects=0

    I don't know where to start. Some of my friends told me that I need an Angle!
    Any advice?
    You can use the cos rule on triangle ABC to find angle B

    \cos(B) = \frac{|AB|^2+|BC|^2 - |AC|^2}{2|AB||BC|}
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  3. #3
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    Re: Area of a Triangle.

    It's also possible to find the area of ABC using Heron's formula, and from there easily find the area of ACD.
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