Weird game of geometry
Source: Serbia TST 2018 P3
May 29, 2018
combinatoricsgeometryGame Theory
Problem Statement
Ana and Bob are playing the following game.
[*] First, Bob draws triangle and a point inside it.
[*] Then Ana and Bob alternate, starting with Ana, choosing three different permutations , and of .
[*] Finally, Ana draw a triangle .For , let be the similarity transformation which takes and to and respectively (here ) where triangle lies on the outside of triangle . Finally, let . Ana wins if triangles and are similar (in some order of vertices) and Bob wins otherwise. Determine who has the winning strategy.