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Math Help - angle of the triangle

  1. #1
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    Question angle of the triangle

    calculate the largest angle of a triangle in which one angle is eight times each of the others.

    nedd help...
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  2. #2
    Member SengNee's Avatar
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    Quote Originally Posted by hi00000 View Post
    calculate the largest angle of a triangle in which one angle is eight times each of the others.

    nedd help...
    Let these angles are a,b,c.

    a+b+c=180^o

    a=8b

    b=8c

    Therefore,
    a=64c

    The largest angle is a.

    Erm....I'm not sure....Please tell me either I'm right or not....
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  3. #3
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    the question is frm my maths book ..it says the answer is 144 ...
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  4. #4
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    ...
    Last edited by hi00000; April 27th 2009 at 09:32 PM. Reason: wrote it twise
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  5. #5
    Member SengNee's Avatar
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    Quote Originally Posted by hi00000 View Post
    the question is frm my maths book ..it says the answer is 144 ...
    Maybe the question means:

    a+b+c=180

    a=8b=8c

    Then a=144^o

    Very sorry, my english is not so good.
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  6. #6
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    Angles in a triangle

    Hello hi00000
    Quote Originally Posted by hi00000 View Post
    calculate the largest angle of a triangle in which one angle is eight times each of the others.

    nedd help...
    If the smaller angles are both x^o, then the largest angle is 8x^o. So:

    x +x+8x =180

    \Rightarrow 10x = 180

    \Rightarrow x = 18

    So the largest angle is 8\times 18 = 144^o.

    Grandad
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  7. #7
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    Quote Originally Posted by hi00000 View Post
    calculate the largest angle of a triangle in which one angle is eight times each of the others.

    nedd help...
    a=x
    b=8x
    c=8x

    x + 8x + 8x = 180
    17x = 180
    x = 180/17 = 10.588
    Largest angle = 8x = 84.70
    Last edited by razemsoft21; April 28th 2009 at 10:23 PM.
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  8. #8
    Member SengNee's Avatar
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    Quote Originally Posted by razemsoft21 View Post
    a=x
    b=8x
    c=8x

    x + 8x + 8x = 180
    17x = 180
    x = 180/17 = 10.588
    Largest angle = 8x = 84.70
    Should be

    a=8x
    b=x
    c=x

    Because there is only one largest angle that is 8 times larger than the other two angles.
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  9. #9
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    Red face sorry SengNee

    Quote Originally Posted by SengNee View Post
    Should be

    a=8x
    b=x
    c=x

    Because there is only one largest angle that is 8 times larger than the other two angles.
    you may be right, But the original writer says
    "the question is frm my maths book ..it says the answer is 144 ... "
    depending on understanding the question
    the idea of solving it depend on (the sum of angles of any triangle is 180 degrees."
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