%@Auteur:Arnaud Gazagnes\par \begin{enumerate} \item Donner la propri\'et\'e de l'in\'egalit\'e triangulaire. \item Indiquer, pour chaque triangle, le nom des droites repr\'esent\'ees. {\psset{unit=0.75cm,PointName=none} \begin{pspicture*}(0.1,0)(4.7,6.2) \pstGeonode[PointSymbol=none,PosAngle={90,90,0}](.3,5.6){A}(4.5,5){B}(2.1,.2){C} \pstLineAB{A}{B}\pstLineAB{A}{C}\pstLineAB{B}{C} \pstProjection{B}{C}{A}[H_A] \pstLineAB[nodesepA=-5,nodesepB=-5]{A}{H_A} \pstProjection{A}{C}{B}[H_B] \pstLineAB[nodesepA=-5,nodesepB=-5]{B}{H_B} \pstProjection{A}{B}{C}[H_C] \pstLineAB[nodesepA=-5,nodesepB=-5]{C}{H_C} \pstInterLL[PosAngle=290]{A}{H_A}{B}{H_B}{H} \pstRightAngle{H}{H_A}{C} \pstRightAngle{H}{H_B}{A} \pstRightAngle{H}{H_C}{B} \end{pspicture*} \hfill \begin{pspicture*}(0.1,0)(4.7,6.2) \pstGeonode[PointSymbol=none,PosAngle={90,90,0}](.3,5.6){A}(4.5,5){B}(2.1,.2){C} \pstMiddleAB[PosAngle=140]{A}{B}{C'} \pstMiddleAB[PosAngle=2405]{A}{C}{B'} \pstMiddleAB[PosAngle=270]{B}{C}{A'} \pstInterLL{A}{A'}{B}{B'}{G} \pstSegmentMark[SegmentSymbol=MarkHash]{A}{C'} \pstSegmentMark[SegmentSymbol=MarkHash]{B}{C'} \pstSegmentMark[SegmentSymbol=MarkHashh]{B}{A'} \pstSegmentMark[]{C}{A'} \pstSegmentMark[SegmentSymbol=MarkHashhh]{C}{B'} \pstSegmentMark[SegmentSymbol=MarkHashhh]{A}{B'} \pstLineAB[nodesepA=-5,nodesepB=-5]{A}{A'} \pstLineAB[nodesepA=-5,nodesepB=-5]{B}{B'} \pstLineAB[nodesepA=-5,nodesepB=-5]{C}{C'} \end{pspicture*} \hfill \begin{pspicture*}(0.1,0)(4.7,6.2) \pstGeonode[PointSymbol=none,PosAngle={90,90,0}](.3,5.6){A}(4.5,5){B}(2.1,.2){C} \pstLineAB{A}{B}\pstLineAB{A}{C}\pstLineAB{B}{C} {\psset{CodeFig=true,CodeFigColor=black,nodesepA=-15,nodesepB=-5,PointSymbolB=none}\pstMediatorAB[SegmentSymbol=MarkHash]{C}{B}{A'}{M_A} \pstMediatorAB{B}{A}{C'}{M_C} \pstMediatorAB[SegmentSymbol=MarkHashhh]{A}{C}{B'}{M_B}} \pstInterLL{A'}{M_A}{B'}{M_B}{O} \end{pspicture*}} \item Donner la d\'efinition d'une\dots \begin{enumerate} \item m\'ediatrice \item m\'ediane \item hauteur \end{enumerate} \item A quel type de droites est li\'e le centre du cercle circonscrit ? \end{enumerate}