Parabola as a Locus of Points

Uses the Locus tool to demonstrate the locus of points which is the parabola. All points which are equadistant from a point (the focus) and a line (the directrix). Manipulate the distance with the slider and note how the distance from the focus to the point and the distance of the point to the directrix are the same.
To see the construction of the demonstration, turn on for display some of the objects listed in the Algebra window.