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Math Help - Circle and three lines

  1. #1
    Newbie joesmith13610's Avatar
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    Circle and three lines

    Hello everyone I am new to the forums. I didnt know where to put this one, either in the high school or college section.


    I was wondering if you guys/gals can help me out with this problem.
    I dont really know how to start the problem.

    here you go:

    We are given three infinite straight lines. we need to construct a circle that touches the first two lines and has its center on the third line?

    Any help is appreciated.

    thanks everyone


    joe
    Last edited by joesmith13610; October 4th 2008 at 06:03 PM.
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by joesmith13610 View Post
    Hello everyone I am new to the forums. I didnt know where to put this one, either in the high school or college section.


    I was wondering if you guys/gals can help me out with this problem.
    I dont really know how to start the problem.

    here you go:

    We are given three infinite straight lines. we need to construct a circle that touches the first two lines and has its center on the third line?

    Any help is appreciated.

    thanks everyone


    joe
    what do we know about the lines? are they parallel, perpendicular, skew? was that all the info you were given?
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  3. #3
    Super Member

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    Hello, Joe!

    Welcome aboard!


    We are given three infinite straight lines.
    We need to construct a circle that is tangent to the first two lines
    and has its center on the third line.
    Code:
                   L2 /                   /
                     /                   /
                    /                   ♥ C
                   /                 o /
                  /               o   /
                 /             o     /
                /           o       /
               /         o         / L3
              /       o           /
             /     o             /
            /   o               /
    L1     / o                 /
      - - * - - - - - - - - - * - - - - - -
         /                   /
        /                   /
    Assuming that the lines intersect . . .


    Construct the bisector of the angle formed by L_1 and L_2.
    . . The center of our circle lies on this angle bisector.

    Locate the intersection C of the angle bisector and L_3.
    . . C is the center of the circle

    Determine the perpendicular distance from C to L_1 (or to L_2).
    . . That is the radius of the circle.

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  4. #4
    Newbie joesmith13610's Avatar
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    Quote Originally Posted by Jhevon View Post
    what do we know about the lines? are they parallel, perpendicular, skew? was that all the info you were given?

    that was all the info we got.


    joe
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