Problem

Source: 239 2008 J4

Tags: geometry



Point $P$ is located inside an acute-angled triangle $ABC$. $A_1$, $B_1$, $C_1$ are points symmetric to $P$ with respect to the sides of triangle $ABC$. It turned out that the hexagon $AB_1CA_1BC_1$ is inscribed. Prove that $P$ is the Torricelli point of triangle $ABC$.