categories:
- Counting geometry
- Triangle geometry
- Четырехугольники и многоугольники
- Circle and other
- New draw
- Combinatoric geometry
- Other
Problem #34
9 - 10 Grade:
Two unequal circles intersect at A and B. The two common tangents touch one circle at P, Q and the other at R, S. Show that the orthocenters of APQ, BPQ, ARS, BRS form a rectangle.