Pascalgerade

source  =  
        DirectoryName[
          ToFileName["FileName" /. 
              NotebookInformation[EvaluationNotebook[]]]];
SetDirectory[source];
Needs["GeoBeweiser`"]

clearndg[];
Clear[u1, u2, u3, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, 
        x13, x14, y];

vars := {x1, x2, x3, x4, x5, x6, y};
parameters := {u1, u2, u3};

P1 = 
      point[0, 0]; P2 = point[u1, u2];

    P3 = point[u3, u4]; P4 = point[x1, x2]; P5 = point[x3, x4]; 
    P6 = point[x5, x6];

A = 
      intersectionpoint[ppline[P1, P2], ppline[P4, P5]]

B = intersectionpoint[ppline[P2, P3], ppline[P5, P6]]

Unprotect[C];
C = intersectionpoint[ppline[P3, P4], ppline[P6, P1]]

kKreis = p3circle[P1, P2, P3]

AddGleichung[
      oncircle[P4, kKreis]]

AddGleichung[oncircle[P5, kKreis]]

AddGleichung[oncircle[P6, kKreis]]

polys=Map[Numerator[Together[#]] &, Gleichungen]

con = Numerator[Together[online[C, ppline[A, B]]]] // Timing

IdealMember[con, polys, vars] // Timing