beginfig(1); numeric u; u=1cm; pair A,B,C,D,E,F,G,H,I,J,K,L,N,X; A=origin; B-A=(7u,0); C-A=(u,5u); D=.5[A,B]; E=.5[B,C]; F=.5[A,C]; G=whatever[B,C]=whatever[A,A+((C-B) rotated 90)]; H=whatever[A,C]=whatever[B,B+((C-A) rotated 90)]; I=whatever[A,B]=whatever[C,C+((B-A) rotated 90)]; X=(A--G) intersectionpoint (C--I); J=.5[A,X]; K=.5[B,X]; L=.5[C,X]; N=whatever[.5[D,I],(.5[D,I]+((D-I) rotated 90))] =whatever[.5[D,H],(.5[D,H]+((D-H) rotated 90))]; r=arclength(I--N); draw A--B--C--cycle; draw A--G; draw B--H; draw C--I; draw fullcircle scaled 2r shifted N; label.top(btex $C$ etex,C); label.lft(btex $A$ etex,A); label.rt(btex $B$ etex,B); endfig; end