# Steiner-Lehmus Theorem
Let(A=[-u1,0], B=[u1,0], C=[u2,u3], A1=[x1,x2], B1=[x3,x4]):
SteinerLehmusA := Theorem(
    [equiangle(C,A,A1,A1,A,B), equiangle(A,B,B1,B1,B,C),
     collinear(B,A1,C), collinear(A,B1,C), equidistance(A,A1,B,B1)],
    equidistance(A,C,B,C), [u2,x1,x2,x3,x4]);
