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Math Help - Triangle

  1. #1
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    Triangle

    To prove that sum of two sides of a triangle minus the third side is less than the third side?
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  2. #2
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    let the sides be a,b,c so you have to prove a+b-c<c

    Keep in mind a+b>c
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  3. #3
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    ?
    Last edited by soni; July 14th 2010 at 10:24 PM.
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  4. #4
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    Quote Originally Posted by soni View Post
    but how i can prove that a + b > c ?
    That is a given otherwise you would not have a triangle.
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  5. #5
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    will you give me proof of this question i.e. a + b - c < c ?
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  6. #6
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    Let's re-write it like this

    a + b - c < c

    c> a + b - c

    and because a+b>c then it still holds that

    a+b> a + b - c

    now given a,b, c>0 then we must be finished!
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  7. #7
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    Thanks a lot
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