1. Illustration of well known geometry facts using
the move mode and the animation mode
We consider the pedal triangle PQR of the triangle ABC with respect to the point X. We ask for the locus of X while the
pedal triangle degenerates into a line of collinear points [PQR]. This straight line is called the "WALLACE-line of the
triangle ABC with respect to the point X". This line is also called SIMSON-line.
Figure 1
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Figure 2
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Using the move mode in figure 1 we see, that the solution is the circumcircle u of the triangle ABC. This is an
example for the useful tool "Bind a Point on a Line", which will be available in version 2 of CINDERELLA. Figure 2 shows
the solution in the animation mode.
Hint: In figure 1 and all following figures without animations
you can move the red colored points like by mouse-clicking.
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