2026-10-202026-10-202026-05-29SILVA, Admilson Amilcar Martins da. Ensino de polígonos no 9°ano do ensino fundamental: uma sequência didática orientada pelo desenho geométrico e pela teoria das situações didáticas de Brousseau. Orientadora: Eliza Souza da Silva. 2026. 152 f. Dissertação (Mestrado Profissional em Ensino de Matemática) - Centro de Ciências Sociais e Educação, Universidade do Estado do Pará, Belém, 2026.https://portaldaposgraduacao.uepa.br/handle/riuepa/365AbertoDesenho geométricoEnsino de GeometriaPolígonoSoma dos ângulos internosTeoria das Situações DidáticasEngenharia DidáticaGeometric drawingGeometry teachingPolygonsSum of interior anglesTheory of didactical situationsDidactic engineeringDissertaçãoCiências HumanasThe learning of Geometry in lower secondary education still presents challenges related to conceptual understanding, spatial visualization, and the articulation between representation, argumentation, and mathematical formalization. In many school contexts, geometry teaching remains centered on the reproduction of formulas and procedures, limiting students’ investigative participation and hindering the meaningful construction of concepts. In this context, geometric drawing emerges as a didactic-methodological alternative capable of bringing students closer to mathematical experimentation by fostering processes of observation, analysis, conjecture, and validation. Thus, this research sought to answer the following question: how can geometric drawing contribute to the understanding of the sum of the interior angles of polygons among ninth-grade students? The general objective was to analyze the contributions of geometric drawing to the understanding of the sum of the interior angles of polygons in a ninth-grade class. This study is grounded in Guy Brousseau’s Theory of Didactical Situations and Michèle Artigue’s Didactical Engineering, theoretical frameworks within the French Didactics of Mathematics that supported the design, implementation, and analysis of a didactic sequence focused on polygons and their angular properties. The research adopted a mixed-methods approach and was conducted in a public school in the city of Belém, Brazil. It involved activities of construction, representation, and investigation of polygons through the use of geometric drawing instruments, with triangulation serving as a strategy for exploring geometric relationships. Data were collected through classroom observations, written records of activities, diagnostic tests administered before and after the pedagogical intervention, and evaluation questionnaires. The results revealed improvements in students’ understanding of polygon properties and the sum of their interior angles, as well as in the development of geometric reasoning, mathematical argumentation, and active participation during the proposed didactical situations. The experimental activities promoted the formulation of conjectures, the validation of strategies, and the progressive construction of geometric concepts, indicating that the use of geometric drawing instruments can help overcome teaching practices based exclusively on the memorization of procedures. As an outcome of the research, an educational product entitled Practical Guide to Geometric Drawing: Construction of Polygons and Their Angles was developed to support teachers through methodological guidelines and classroom activity proposals. It is concluded that geometric drawing, when articulated with the assumptions of the Theory of Didactical Situations and Didactical Engineering, has significant potential for Geometry teaching, fostering investigative practices, intellectual autonomy, and more critical, reflective, and conceptually consistent learning processes.PPGEM - Metodologia para ensino de matemática no nível fundamental