% Centre de gravite
% 1. Definition des points caracteristiques de la geometrie
\figinit{4cm,ortho}
% Sommets
\figpt 1:$A$(0.5,0.8,1.3)
\figpt 2:$B$(0,0)
\figpt 3:$C$(1,0.5)
\figpt 4:$D$(0,1.4)
\figptbary 5:$G$[1,2,3,4;1,1,1,1] % Centre de gravite
\figptbary 6:$G_A$[2,3,4;1,1,1]
\figptbary 7:[2,4;1,1]
\figptbary 11:$I$[1,2;1,1]\figptbary 12:$I'$[3,4;1,1]
%
\figset proj(psi=20)
% 2. Creation du fichier graphique
\figdrawbegin{}
% Aretes externes du tetraedre
\figset(join=round)
\figdrawline[1,2,3,1,4,3]
\figset(dash=2)\figdrawline[2,4]
\figset(dash=4)\figdrawline[11,12]\figdrawline[1,6]\figdrawline[3,7]
\figdrawend
% 3. Inscription du texte sur le dessin
\def\dist{2pt}
\figvisu{\figBoxA}{\it Centre de gravit\'e \rm(p. 129)}{%
\figwriten 1:(\dist)\figwritenw 2,11:(\dist)
\figwritesw 3:(\dist)\figwritene 4:(\dist)
\figwritese 6,12:(\dist)
\figset write(mark=$\figBullet$)\figwritee 5:(3pt)
}
\centerline{\box\figBoxA}