Pappus' Theorem

Given that the points D, E, F, G, I, J lie on the lines α and β, the lines s and w are parallel, and the lines t and v are also parallel, the lines a and b must be parallel as well.

Use the slider Ω for a step by step construction of Pappus' Theorem.

The lines α and β can be changed by clicking and moving any of the points O, M, N, and P. The lines s, t, v, w can also be changed by moving the points D, E, F, G.

Mike Bauders, March 6, 2011, Created with GeoGebra