## Problem of the Week

**Geometry Series #3**

-------10/22/07-------

Prove the following theorem:

Let AO (where O is the center of triangle ABC) intersect the circumcircle again in Y. Then BHCY is a parallelogram, and the circle through the six points found above also passes through the midpoints of BC, CA, and AB.

*(*

__Geometry: A Comprehensive Course__)