Determine all triangles that can be split into two congruent pieces by one cut. A cut consists of segments $P_1P_2$, $P_2P_3$, . . . , $P_{n-1}P_n$ where points $P_1, P_2, . . . , P_n$ are distinct, points $P_1$ and $P_n$ lie on the perimeter of the triangle and the rest of the points lie in the interior of the triangle such that the segments are disjoint except for the endpoints.
Problem
Source: (2021 -) 2022 Dürer Math Competition Regional E+2 https://artofproblemsolving.com/community/c1621671_
Tags: combinatorial geometry, congruent triangles, geometry