Teorema de Pappus: superfícies e sólidos de revolução

Abstract

This research intends to demonstrate how efficient and how easy the use of Pappus'centroid the-orems can be at solving problems of surface areas and solids of revolution. The use of centroid theorems is one of the many contributions Pappus of Alexandria made to Mathematics through his work, The Synagogue. Currently, Pappus'theorems are not studied in Secondary Education and are not commonly studied in university; on the other hand, surface areas and solids of re-volutions are studied both in Secondary Education and university level whilst Pappus'theorems can be used to simplify the calculations of surface areas and solids of revolution. The research also addresses the centre of gravity of simple plane figures, which is of extreme importance in the application of the theorems. Finally, theorems and propositions of Calculus were used for the demonstration of the two theorems of Pappus.