MathDB

10

Part of 2009 Sharygin Geometry Olympiad

Problems(1)

Determine angle C

Source: I.F.Sharygin contest 2009 - Correspondence round - Problem 10

5/31/2009
Let ABC ABC be an acute triangle, CC1 CC_1 its bisector, O O its circumcenter. The perpendicular from C C to AB AB meets line OC1 OC_1 in a point lying on the circumcircle of AOB AOB. Determine angle C C.
geometrycircumcircletrapezoidperpendicular bisectorgeometry proposed