Line-Circle and Two Circles
This activity belongs to the GeoGebra book GeoGebra Principia.
The locus of points equidistant from a line and a circle is generally composed of one parabola or, if they intersect, two parabolas.
The locus of points equidistant from two circles is generally composed of a branch of a hyperbola or, if they intersect, an ellipse.
Author of the construction of GeoGebra: Rafael Losada.