reserve a,a1,a2,a3,b,b1,b2,b3,r,s,t,u for Real;
reserve n for Nat;
reserve x0,x,x1,x2,x3,y0,y,y1,y2,y3 for Element of REAL n;
reserve L,L0,L1,L2 for Element of line_of_REAL n;
reserve P,P0,P1,P2 for Element of plane_of_REAL n;

theorem Th99:
  ex P st x in P & L c= P
proof
  L in line_of_REAL n;
  then consider x1,x2 being Element of REAL n such that
A1: L = Line(x1,x2);
  take P = plane(x,x1,x2);
  x1 in P & x2 in P by Th82;
  hence thesis by A1,Th82,Th85,Th90;
end;
