Uma breve introdução à geometria plana.

Abstract

This work aims to show the elegance of geometry together with the importance of the knowledge that ancient peoples used this area in antiquity, starting with the Babylonian, Indian, Egyptian, Greek and Chinese peoples. In addition, we will present some important mathematicians who have made studies in geometry and provided contributions, making geometry as we know it today. From this, primitive concepts will be approached that are accepted without demonstration for which, using the postulates of determination and inclusion, to enunciate the usual geometry, starting with point, straight and then approaching the contents of angles. In the sequence, the triangle, quadrilateral, hexagon polygons will be presented, defining perimeter and then area of the polygons, in addition to providing example of area calculation in different ways. We will deal with the Heron formula that is used to calculate the area of any triangle, using its semi- ́ meter. At the end of the work, some important theorems will be enunciated and demonstrated, namely, Theorems of Pythagoras, which has about 370 demonstrations and will be presented two in this work, and Tales Theorem. In addition to these theorems, Bramagupta’s Theorem is also stated and demonstrated, an important result within geometry.