Esplorazioni geometriche (3°): Cabri e le affinità

In order to illustrate the classical methods of affine geometry (which today are not widely known because university studies mainly approach geometry algebraically), this paper shows the use of Cabri for creating two 'macros' allowing to construct the correspondent of a point in the (direct or inverse) affine transformation individuated by any t\vo triangles. In order to make our presentation more interesting and fruitful, we pay special attention to heuristic aspects and to the contents connected with the problems tackled. For this reason, as in the previous papers of the series (cfr. Pellegrino & Bonacini 1997, Pellegrino 1997, Pellegrino & Barozzi 1997a and 1997b), besides presenting some solutions, we discuss the various features which lead to the individuation and refinement of the solutions suggested.