autocrop
-2 19 setxrange
-2 10 setyrange
12 setxunit
/x 6 def

/A {0 0} def
/B {18 0} def
/C {0 8} def

/D {0 x} def
/E {15 x sub 0} def

B A C angledroit
1.2 setlinewidth
[A B C] polygone
[D E] points
[D E] ligne

setTimesItalic
   (A) A dltext
   (B) B drtext
   (C) C ultext
   (D) D ultext
   (E) E dltext

gsave
   -10 0 translate
   .5 setlinewidth
   A D (<->) line
   (x) A D milieu cltext
grestore

gsave
   0 -10 translate
   .5 setlinewidth
   B E (<->) line
   (x) B E milieu dctext
grestore