-2.5 5 setxrange -0.5 3 setyrange 50 setxunit 50 setyunit /A {0 0} def /B {4 0} def /C {1 2} def /D {1 0} def C D B angledroit [A B C] polygone gsave pointilles [C D] ligne grestore $a$ 2.9 0.9 [1.8 dup] ultexlabel $b$ 0.15 1.1 [1.8 dup] crtexlabel $c$ 2.1 0.05 [1.8 dup] dctexlabel (A) A [1.5 dup] dltext (B) B [1.5 dup] drtext (C) C [1.5 dup] uctext (C') D [1.5 dup] dctext $\rm{Abb}.\,2\ \ \ a)$ -0.5 0.8 [2.0 dup] ultexlabel