Constructing an Ellipse Locus in GeoGebra

This GeoGebra example demonstrates how to construct an ellipse as a locus: the curve formed by points whose sum of distances to two fixed points remains constant. It centers on the definition of an ellipse in terms of a distance-sum invariant, along with the general concept of a locus (locus construction). The construction uses core geometry tools: Circle to build distance-related circles, Point to create and track key points, Line and LineBisector to form supporting geometric constructs, Intersect to compute intersection points that satisfy the required constraints, and Locus to trace the resulting locus curve (e.g., loc1). The activity is well suited for high school and early university learners studying coordinate geometry/analytic geometry and for classroom demonstrations of how geometric constraints generate recognizable conic sections via interactive graphing.