925Crux 2840, proposed by Juan-Bosco Romero Marquez, University ́
of Valladolid, Valldolid, Spain
LetA′be an interior point of the line segmentBCin triangleABC. The
interior bisectors of∠BA′Aand∠CA′AintersectABandCAatDand
Erespectively. Prove thatAA′,BE, andCDare concurrent.