%@Auteur: Arnaud Gazagnes\par Parmi les quadrilat\`eres suivants, indique ceux qui te semblent \^etre des parall\'elogrammes. \begin{center} \psset{unit=0.35cm} \begin{pspicture}(1,1)(19,18) \pspolygon(1,5)(3,8)(5,5)(3,2) \pspolygon(7,1)(7,7)(12,5)(13,1) \pspolygon(16,1)(15,6)(18,7)(19,2) \pspolygon(1,9)(1,14)(5,14)(5,9) \pspolygon(8,9)(7,14)(11,14)(14,9) \pspolygon(16,9)(17,14)(19,14)(18,9) \pspolygon(1,18)(5,18)(7,15)(3,15) \pspolygon(9,15)(10,18)(13,18)(14,15) \pspolygon(16,15)(16,18)(19,18)(19,15) \rput(3,4.5){\Large{$G$}} \rput(10,3){\Large{$H$}} \rput(17,3){\Large{$I$}} \rput(17.5,11.5){\Large{$F$}} \rput(10.5,11){\Large{$E$}} \rput(3,11){\Large{$D$}} \rput(17.5,16.5){\Large{$C$}} \rput(11.5,16.5){\Large{$B$}} \rput(4,16.5){\Large{$A$}} \end{pspicture} \end{center}