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Math Help - Triangle

  1. #1
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    Triangle

    Hello


    A triangle has one side that is 7 and another side that is 12. What it the max and min value for the third side.



    Thank you for any help
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  2. #2
    Behold, the power of SARDINES!
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    Quote Originally Posted by Makron View Post
    Hello


    A triangle has one side that is 7 and another side that is 12. What it the max and min value for the third side.



    Thank you for any help
    If you know the law of cosines then

    c^2=a^2+b^2-2ab\cos(\theta)

    c^2=49+144-168\cos(\theta)

    Can you finish from here?
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  3. #3
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    Thank you for helping =)

    but the angle is unknown ?
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  4. #4
    A riddle wrapped in an enigma
    masters's Avatar
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    Quote Originally Posted by Makron View Post
    Hello


    A triangle has one side that is 7 and another side that is 12. What it the max and min value for the third side.



    Thank you for any help
    Hi Makron,

    If the third side is  x , then 5 < x < 19

    Essentially, the third side must be greater then the difference of the other two sides, but less than their sum.
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  5. #5
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    thank you but I would like to know how to complete the ekvation that "Emptyset" posted
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  6. #6
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    The equation was c^2= 49+ 25- 168cos(\theta). The angle \theta can be any angle between 0 and 180 degrees. What is that equation if \theta= 0? What if \theta= 180?
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