Let $A,B,C,D,E,F$ be the midpoints of consecutive sides of a hexagon with parallel opposite sides. Prove that the points $AB\cap DE$, $BC\cap EF$, $AC\cap DF$ lie on a line.
Problem
Source: Mongolia MO 2001 Grade 10 P5
Tags: geometry, hexagon, projective geometry
PROF65
12.04.2021 16:57
is there any thing missing.
jasperE3
12.04.2021 17:04
Not as far as Imomath tells me. I checked with a diagram too.
PROF65
12.04.2021 17:29
if the concurrency is met then $ABCDEF$ should be inscriptible in a conic but look at the example in the diagram below
Attachments:
i3435
15.04.2021 03:57
@above it says $\overline{AC}\cap\overline{DF}$. By Pascal's the hexagon's vertices are coconic. Affine transform their circumconic to a circle. By Desargues we have to show that $\overline{AD},\overline{BE},\overline{CF}$ are concurrent. Since they all pass through the center of the circle, we are done.
PROF65
15.04.2021 19:23
Thanks for indicating my misreading.