Modeling of Teaching–Learning Process of Geometrical LOCI in the Plane with GeoGebra

GeoGebra is an open-source software that has been widely used for teaching and learning mathematics worldwide. Other than the English interface, GeoGebra also supports Vietnamese, making it suitable for mathematics education in Vietnam, at school level and higher. As GeoGebra can combine calculation and dynamic drawing of geometrical objects, it is quite effective in geometry classes. This article showed how GeoGebra could be used for teaching lessons on geometrical loci (sets of points satisfying certain conditions). In addition to basic loci, we also illustrated the ability of GeoGebra in solving hard loci (in mathematical competitions) and expanding knowledge of geometrical loci for school students and undergraduates.