In the parallelogram ABCD, ab ∥ CD, ad ∥ BC, e and F are on AD and CD respectively, and CE = AF. CE and AF intersect at point P, and In the parallelogram ABCD, ab ∥ CD, ad ∥ BC, e and F are on AD and CD respectively, and CE = AF, CE and AF intersect at point P, and Pb bisection ∠ APC is proved

In the parallelogram ABCD, ab ∥ CD, ad ∥ BC, e and F are on AD and CD respectively, and CE = AF. CE and AF intersect at point P, and In the parallelogram ABCD, ab ∥ CD, ad ∥ BC, e and F are on AD and CD respectively, and CE = AF, CE and AF intersect at point P, and Pb bisection ∠ APC is proved

Connect AC, BD, the intersection point is O, then the angle OAM = angle OCN, Ao = Co, because: angle AOM = angle con, so: Triangle AOM ≌ triangle con similarly: Triangle Bon ≌ triangle DOM, because: Ao = Bo = co = do, angle AOB = angle cod, so: triangle AOB ≌ triangle cod congruent triangle area is equal s (abnm) = s (triangle AOM) +