In mathematics, Pappus's hexagon theorem states that given one set of collinear points A, B, C, {\displaystyle A,B,C,} and another set of collinear points a, b, c, {\displaystyle a,b,c,} then the intersection points X, Y, Z {\displaystyle X,Y,Z} of line pairs A b {\displaystyle Ab} and a B, A c {\displaystyle aB,Ac} and a C, B c {\displaystyle aC,Bc} and b C {\displaystyle bC} are collinear, lying on the Pappus line. Wikipedia