The aim of this paper is to document and analyze reasoning processes developed by mathematics bachelor students when they approach geometry problems at the end of a problem solving course. The conceptual framework that guided data interpretation was structured around problem solving model together with a characterization of superficial and well-founded ways of reasoning. The methodology supporting the study was qualitative; the data recollection sources included informal interviews and students’ written productions. The main results indicate that students’ reasoning processes were strongly influenced by visualization of geometric configurations and by the teacher interventions. We observed that the creative reasoning supersedes the imitative one. However, in some cases, the creative reasoning was oriented only by plausible arguments.

problem solving, reasoning, geometry.