The use of dynamic geometry and mathematical investigation in the validation of geometric properties

This paper presents an activity on Geometry of position using GeoGebra software, based on Mathematical Investigation. The Dynamic Geometry, through software, becomes a tool for the formation of a mental image of abstract objects and motivation to introduce the idea of justifying its properties through arguments external to software. Allied to Dynamic Geometry, Mathematical Investigation guides the possible ways to construct conjectures and justifications and emphasizes that conjecture and looking for properties are as important as demonstrating them, since it shows the Mathematics as a knowledge in construction and favors the cognitive evolution of the relation between perception and abstraction. The activity was applied and it was observed that, from it, the student can formulate conjectures and develop logical and formal argumentation skills that are essential to construct geometric objects from their properties