/B {-1.5 -1.5} def
/A {-1 3} def
/C {3 0} def
-2.5 4 setxrange
-2.5 4 setyrange
30 setxunit
30 setyunit
%% les milieux
/J {B C milieu} def
/I {A B milieu} def

%% on marque les longueurs
B I 2 marked
I A 2 marked
B J 1 marked
J C 1 marked

1.7 setcurvelinewidth
[B A C] polygone


.7 setcurvelinewidth
[J I] ligne

setTimesItalic
   (B) B [2.5 2.5] dltext
   (A) A [2.5 2.5] urtext
   (C) C [2.5 2.5] drtext
   (J) J [2.5 2.5] drtext
   (I) I [2.5 2.5] ultext
%% adresse IP : 193.52.218.80