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[parent] compass and straightedge construction of angle bisector (Algorithm)

One can construct the (interior) angle bisector of a given angle using compass and straightedge as follows:

  1. With one point of the compass on the vertex of the angle, draw an arc that intersects both sides of the angle.

    \begin{pspicture}(0,-1)(3,3) \psarc[linecolor=blue](0,0){1}{-25}{80} \psline{o->}(0,0)(3,0) \psline{o->}(0,0)(2,3) \psdots(0,0)(1,0)(0.5547,0.832) \end{pspicture}
  2. Draw an arc from each of these points of intersection so that the arcs intersect in the interior of the angle. The compass needs to stay open the same amount throughout this step.

    \begin{pspicture}(0,-1)(3,3) \psarc(0,0){1}{-25}{80} \psline{o->}(0,0)(3,0) \psl... ...0.832){1}{-30}{30} \psdots(0,0)(1,0)(0.5547,0.832)(1.5548,0.832) \end{pspicture}
  3. Draw the ray from the vertex of the angle to the intersection of the two arcs drawn during the previous step.

    \begin{pspicture}(0,-1)(3,3) \psarc(0,0){1}{-25}{80} \psline{o->}(0,0)(3,0) \psl... ...}(0,0)(3,1.605351) \psdots(0,0)(1,0)(0.5547,0.832)(1.5548,0.832) \end{pspicture}

This construction is justified because the point determined in the second step is equidistant from the two rays and thus must lie on the angle bisector.

If you are interested in seeing the rules for compass and straightedge constructions, click on the link provided.



"compass and straightedge construction of angle bisector" is owned by Wkbj79.
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Other names:  construction of angle bisector
Keywords:  Euclidean geometry

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Cross-references: compass and straightedge constructions, lie on, vertex, ray, intersects, arc, point, straightedge, compass, angle, angle bisector
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This is version 15 of compass and straightedge construction of angle bisector, born on 2007-06-03, modified 2007-06-13.
Object id is 9502, canonical name is CompassAndStraightedgeConstructionOfAngleBisector.
Accessed 1368 times total.

Classification:
AMS MSC51-00 (Geometry :: General reference works )
 51M15 (Geometry :: Real and complex geometry :: Geometric constructions)

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