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Math Help - known circle inside of a 60 degree angle?

  1. #1
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    known circle inside of a 60 degree angle?

    A friend of mine is trying to machine apart.

    We have a circle of known diameter. Picture a this circle inside of a 60 degree angle. We need to know how far the tangents are from the corner of the angle.

    How would we set this up.

    Thanks
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  2. #2
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    Lets say the circle is one inch. There is a 60 degree angle. How far away is the corner of the angle from either of the tangents where the circle is contacting both side of the 60 degree angle.
    Last edited by jonb; April 21st 2010 at 04:23 AM.
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  3. #3
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    Quote Originally Posted by jonb View Post
    Lets say the circle is one inch. There is a 60 degree angle. How far away is the corner of the angle from either of the tangents where the circle is contacting both side of the 60 degree angle.
    Corner of the angle , center and the point of contact of the tangent form a right angled triangle with 30-90-60 angles.
    Now you can find easily relation between the sides and the length of the tangent.
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  4. #4
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    Hello, jonb!

    sa-ri-ga-ma has the best approach!


    We have a circle of known diameter.
    Picture this circle inside of a 60 angle.
    We need to know how far the tangents are from the corner of the angle.

    How would we set this up?
    Code:
                       /
                      /   * * *
                     /*           *
                    *               *
                   *                 *
                  /
                 /*         O         *
                / *         *         *
               /  *      *  |         * 
              /       *     |
             /     *        |r       *
            /   *   *       |       *
           / * 30    *     |     *
          * - - - - - - - * * *
          A                 B

    \Delta OBA is a 30-60-90 right triangle.

    We have: . \angle OAB = 30^o,\;OB = r

    You can now find AB.

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