Teorema de Tales: análise de sua apresentação nos livros didáticos e proposição de atividades

Abstract

In this work we identify the goals and guidelines the National Curriculum Guidelines, the third and fourth cycles, on the study of geometry. We searched on the Biography of Thales of Miletus, where we do a story, and history of the region, the era in which he lived, we count some of their deeds, and enumerate the theorems whose statements are allocated. We analyzed six textbooks in 9th grade of elementary school, comprising the National Plan of Didactic Book 2014, observed how the geometry is crafted, and what activities and statements made with respect to the Thales’ Theorem. We use and recommend the Geogebra software for the study of geometry. We propose diversified activities for use in the classroom when the Thales’ Theorem is working. We suggest a demonstration of Thales’ Theorem, where we use the definition of the triangle area, and properties of the parallelogram.