The Shoelace Formula
We begin this work with a chapter that addresses the relationship between the calculus of determinants and the formulas for the areas of polygons and volumes of parallelepipeds and their respective proofs.
These concepts are required for the development of the main theme, which is the shoelace formula. It is presented in the first chapter, along with its proof.
Next, we present a classroom activity, which serves as an example and motivation for using the shoelace formula in a practical way, and not just as one more practical device to be memorized by students. Within this same chapter, we present a lecture plan to run this activity.
In the second part of this dissertation, the focus is on the origins, properties, the existence and uniqueness of the determinants. Those are extremely important results and bring the beauty of mathematical rigor to this study matter, with the purpose to provide a deeper understanding to teachers and the curious readers.
Finally, we conclude that the use of this practical device, the shoelace formula, in addition to facilitating the student's understanding of the concepts of determinants, geometry and analytical geometry, allows the students to understand the different ways of using mathematics in everyday life.