The most important theories in geometry education that were identified and discussed
are the following: Van Hiele’s levels, Geometrical Working Space and Geometrical
paradigms and Duval’s semiotic approach. Each line of theory approaches geometry
learning from a different perspective and thus is helpful for different purposes. Van
Hiele’s theory is mainly helpful for evaluating students’ reactions, productions and
solutions to problems (phenomenological approach). Houdement and Kuzniak’s
(2003) theory about Geometrical Working Space and Geometrical Paradigms (e.g.
Geometry I: Natural Geometry, Geometry II: Natural Axiomatic Geometry and
Geometry III: Formal Axiomatic Geometry) is mainly helpful for classifying
approaches, e.g. the types of argumentation used and to understand students’