This study is the result of thoughts and reflections focused on the encouragement of a critical and meaningful teaching of Mathematics on basic education level and advocates the use of technology in classroom. In particular, topics related to perimeter calculations, areas and volumes are covered, to the public of the Young and Adults Education Program. This Program is in force at the Rio de Janeiro s City Hall since 1984 and meets a considerable portion of the population which, for some reason, could not complete regular education on the predicted age. It was intended, through the thoughts and reflections presented in the first chapters to bring the students daily life closer to the Mathematics World, showing that geometrical aspects are common in their lifes. It was intended too, also, to promote criticality through the encouragement of debates and exchange of experiences and knowledge. Geometry requires a careful look with regard to the space comprehension and the objects form. Therefore, we sought the development of suitable methods that stimulate that look, to the public. The thoughts and reflections developed generated an educational product consisting in a sequence of activities created and applied to PEJA students. The activities and their results are shown in the final chapters of this study. We hope that this study can collaborate with other teachers, interested in creating compromised paths, in the Basic Education, to promote a critical and meaningful education that encourages the autonomy of all.