Geometrical reasoning in the intersection between historical original sources and the dynamic geometry environment GeoGebra

This paper addresses how an interplay between original sources and digital tools can support students’ possibilities to develop the constructive facet of the reasoning competency among 7th grade students. This is done through a use of the distinction between epistemic and pragmatic mediations. The case described takes its outset in a pair of students’ work with (part of) Euclid’s proposition 6, Book IV: To inscribe a square in a given circle. Firstly, the study shows how students’ work with an original source can be seen as a springboard to create their own mathematical arguments, while working with GeoGebra. Secondly, it provides insight to how the above-mentioned theoretical distinction can be seen as a way to highlight some of the opportunities and challenges when working with an original source (with a geometrical content) in interplay with GeoGebra.