Resumen

In this paper we describe one classroom activity, part of a long-term project aimed at investigating the potentialities of dynamic geometry software, namely Cabri-Géomètre, in supporting students’ production of conjectures and proofs in geometry at secondary school level. The paper focuses on the activity of a pair of students solving an open geometry problem in Cabri. The analysis shows that Cabri might be a support in bridging the gap between exploration (and conjecturing) and proof: first, exploration provides students with a wide range of local logical relationships between elements or properties of the figure; then, these local concatenations are to be globally rearranged in the proving phase, in order to construct a complete proof.