@options;
  repereortho(80,370,30,1,1){ 0 , moyen , noir , num1 ,i};
@figure;
  O = point( 0 , 0 );
  M = point( 0 , 7.37 );
  S = point( 7.43 , 0 );
  demiOM = demidroite( O , M );
  demiOS = demidroite( O , S );
  A = pointsur( demiOM , 0.56 );
  cerayA6 = cerclerayon( A , 6 )  { i };
  C = intersection( demiOS , cerayA6 , 1 );
  C1 = intersection( demiOS , cerayA6 , 2 );
  cediaAC = cercledia( A , C )  { i };
  cerayA3 = cerclerayon( A , 3 )  { i };
  B = intersection( cerayA3 , cediaAC , 1 )  { trace };
  B1 = intersection( cerayA3 , cediaAC , 2 )  { i };
  sAC = segment( A , C );
  sAB = segment( A , B );
  sBC = segment( B , C );
  I = milieu( sAC )  { trace };