In Euclidean geometry, a circumcevian triangle is a special triangle associated with a reference triangle and a point in the plane of the triangle. It is also associated with the circumcircle of the reference triangle.
Definition
editLet P be a point in the plane of the reference triangle △ABC. Let the lines AP, BP, CP intersect the circumcircle of △ABC at A', B', C'. The triangle △A'B'C' is called the circumcevian triangle of P with reference to △ABC.[1]
Coordinates
editLet a,b,c be the side lengths of triangle △ABC and let the trilinear coordinates of P be α : β : γ. Then the trilinear coordinates of the vertices of the circumcevian triangle of P are as follows:[2]
Some properties
edit- Every triangle inscribed in the circumcircle of the reference triangle ABC is congruent to exactly one circumcevian triangle.[2]
- The circumcevian triangle of P is similar to the pedal triangle of P.[2]
- The McCay cubic is the locus of point P such that the circumcevian triangle of P and ABC are orthologic.[3]
See also
editReferences
edit- ^ Kimberling, C (1998). "Triangle Centers and Central Triangles". Congress Numerantium. 129: 201.
- ^ a b c Weisstein, Eric W. ""Circumcevian Triangle"". From MathWorld--A Wolfram Web Resource. MathWorld. Retrieved 24 December 2021.
- ^ Bernard Gilbert. "K003 McCay Cubic". Catalogue of Triangle Cubics. Bernard Gilbert. Retrieved 24 December 2021.