a given triangle is divided into n triangles ... tiling triangles related
Source: Spanish Mathematical Olympiad 1987 P3
August 2, 2018
combinatorial geometryTilingtilingsTrianglecombinatorics
Problem Statement
A given triangle is divided into triangles in such a way that any line segment which is a side of a tiling triangle is either a side of another tiling triangle or a side of the given triangle. Let be the total number of sides and be the total number of vertices of the tiling triangles (counted without multiplicity).
(a) Show that if is odd then such divisions are possible, but each of them has the same number of vertices and the same number of sides. Express and as functions of .
(b) Show that, for even, no such tiling is possible