Let D and E be points on sides AB and AC of a triangle ABC such that DB=BC=CE. The segments BE and CD intersect at point P. Prove that the incenter of triangle ABC lies on the circles circumscribed around the triangles BDP and CEP.
Source: 2020 Brazil Cono Sur TST 3.1
Tags: geometry, incenter, circumcircle
Let D and E be points on sides AB and AC of a triangle ABC such that DB=BC=CE. The segments BE and CD intersect at point P. Prove that the incenter of triangle ABC lies on the circles circumscribed around the triangles BDP and CEP.