# Centroid Theorem
Let(A = [-u1,0], B = [u1,0], C = [u2,u3], C1 = [0,0], B1 = [x1,x2],
    A1 = [x3,x4], P = [x5,x6]):
Centroid:=Theorem(
    [arbitrary(A,B,C), midpoint(A,B,C1), midpoint(B,C,A1), midpoint(C,A,B1),
     intersection(A,A1,B,B1,P)], collinear(C,C1,P), [x1,x2,x3,x4,x5,x6]);
