Using Dynamic Geometry Software to Add Contrast to Geometric Situations – A Case Study

There is no lack of suggestions concerning how Dynamic Geometry Software (DGS) may support heuristic approaches to problem solving. However, uses of DGS are often limited purely to a verifying role, in the sense that students are expected to vary or confirm empirically at the computer geometric data which are more or less given. By contrast, it seems worthwhile to seek other uses of DGS which go beyond mere confirmation so that the geometric situation is recognised in its particularity. This paper provides a case study that emerged from a project in which DGS formed an integral part of the pedagogical arrangement. The study is intended to show how the contrasting power of DGS might be utilised in a guided discovery setting.