Triangle similarity: interactions in meshes and slider

Abstract

This article discusses the interactions of (prospective) teachers when performing two tasks in a multiuser, online, virtual, and synchronous version of GeoGebra, the VMTcG. When analyzing the data, the discursive aspects, the modalities of dragging points and the categories of signs present in the process of semiotic mediation are considered. The first episode involves the use of the square grid in a task on congruence of triangles, and the second one, a task on the similarity ratio from a slider. The data make it possible to conclude that the thought processes related to the use of the checkered grid were limited to the exploration of more global properties and relations of ascending aspect, while those related to the use of the slider may represent a more potent form of thought process, which implies both the global observation of properties and the validation of conjectures.