% metapost library for the lualatex package luamesh % vardef circumcircle(expr M,N,P)= % Compute center and radius of the circoncircle of the triangle M N P save a,b,c,circle,rad,center,x,y; path circle; pair center; numeric a,b,c,x[],y[]; x1 := xpart M; y1 := ypart M; x2 := xpart N; y2 := ypart N; x3 := xpart P; y3 := ypart P; 2*x1*a+2*y1*b+c=-(x1**2+y1**2); 2*x2*a+2*y2*b+c=-(x2**2+y2**2); 2*x3*a+2*y3*b+c=-(x3**2+y3**2); center := (-a,-b); rad := sqrt(a**2+b**2-c**2); circle := fullcircle scaled (2.0*rad) shifted center; circle enddef