Epistemological potential of the use of visual diagrams in the demonstration of the external angle theorem

Abstract

In the experience report presented here, we established a discussion about the epistemological potentialities of the use of visual representations in the teaching-learning process of the External Angle Theorem, through the development and application of a practical activity for the Euclidean Geometry discipline´s students, of a Degree Course in Mathematics. The research was developed through a qualitative approach. Data were collected through documents (activities developed by students) and recording of a remote class. For the analysis of the data obtained, the qualitative analysis proposed by Yin (2016) was used. By analyzing the results obtained in the light of the studied literature, in particular Arcavi (2003), we can conjecture that the students were able to construct the demonstration of the External Angle Theorem, which shows that visual representations have potential as a facilitating resource in the process of teaching and learning Mathematics, but, in addition, they can be used as a resource for the construction of a demonstration, which highlights their epistemological potential as a resource for demonstration, justification, reasoning and intuition and creativity.