Let A, B, C, D, E, F be points on a circle and makes a hexagon out of them in an arbitrary order. Then the three points
P1, P2, P3 at which
pairs of opposite sides meet, lie on a straight
line. This line is called the Pascal line of the
hexagon ABCDEF and is one of the 60 Pascal lines created by connecting hexagon vertices in any order.
Pascal's theorem proof