MathDB
rhombus, 4 equal incircles - 2015 Cuba 2.2

Source:

September 20, 2024
geometryrhombus

Problem Statement

Let ABCDABCD be a convex quadrilateral and let PP be the intersection of the diagonals ACAC and BDBD. The radii of the circles inscribed in the triangles ABP\vartriangle ABP, BCP\vartriangle BCP, CDP\vartriangle CDP and DAP\vartriangle DAP are the same. Prove that ABCDABCD is a rhombus,