input geometriesyr16; figure(-1cm,-2cm,7cm,6cm); pair A,B,C,D,O; D=(0cm,0cm); A=(0.8cm,2.6cm); B=(4.3cm,2.1cm); C=(5.8cm,-0.5cm); draw A--B--C--D--cycle withpen pencircle scaled 1bp; O=milieu(A,B); draw arccercle(B,A,O) withpen pencircle scaled 1bp; label.lft("A",A); label.rt("B",B); label.lrt("C",C); label.llft("D",D); marque_p:="croix"; pointe(O); fin; end