MathDB
5 concurrent angle bisectors wanted, 5 given (2016 From Tasks to Tasks, p3 Ukr)

Source:

May 3, 2021
geometryangle bisectorconcurrencyconcurrent

Problem Statement

In fig. the bisectors of the angles DAC\angle DAC, EBD \angle EBD, ACE\angle ACE, BDA\angle BDA and CEB\angle CEB intersect at one point. Prove that the bisectors of the angles TPQ\angle TPQ, PQR\angle PQR, QRS\angle QRS, RST\angle RST and STP\angle STP also intersect at one point. https://cdn.artofproblemsolving.com/attachments/6/e/870e4f20bc7fdcb37534f04541c45b1cd5034a.png