Quadrilaterals with GeoGebra. A Teacher Training Sequence for Teaching Geometry with Free Technologies

At present, a challenge for educating mathematics teachers is to design opportunities that allow the teacher to develop knowledge and skills in order to adequately teach classroom content. This paper describes the design of an instructional sequence for training mathematics teachers in teaching quadrilaterals, based on the use of a Dynamic Geometry program. The proposal is part of a "teaching experiment," a type of research design that carries out group TEM in order to develop a learning model about knowledge regarding quadrilaterals as the subject to be taught, in a dynamic environment. The sequence combines objectives, content, activities and a hypothetical learning trajectory, elements characteristic of the experimental design. In addition, instruction is organized around three main thematic clusters, related to the functionalities and dynamic features of the program, quadrilaterals and their classification.