The Use of Geogebra in Mathematical Proof in the Classroom: studying the Euler line

Abstract

In this study, we adopt a perspective of proof as a particular form of argumentation in mathematics. The study involves an experiment developed with 9th grade students, in which activities related to the triangle and its centres were proposed and carried out. This study follows a qualitative methodology of interpretative nature. Data were collected through participant observation, audio and video recordings of classes, student productions with paper and pencil, and with computers and interviews. Starting with the construction of figures in Geogebra, students structured their mathematical reasoning and ideas and built argumentative chains, which led to proving. The data show that most students were able to explore and formulate conjectures as a path leading to proving. Students recognized the importance of Geogebra as motivating but mainly for allowing experimenting and manipulating figures. The results point to the importance of the activity with Geogebra in construction and manipulation as a springboard to proof.

Key-words:
Proof; Geometry; Geogebra; Triangle; Euler Line