Kosnita's theorem
In Euclidean geometry, Kosnita's theorem is a property of certain circles associated with an arbitrary triangle.
Let be an arbitrary triangle, its circumcenter and are the circumcenters of three triangles,, and respectively. The theorem claims that the three straight lines,, and are concurrent. This result was established by the Romanian mathematician Cezar Coşniţă.
Their point of concurrence is known as the triangle's Kosnita point. It is the isogonal conjugate of the nine-point center. It is triangle center in Clark Kimberling's list. This theorem is special case of Dao's theorem on six circumcenters associated with a cyclic hexagon in.
