Given a convex polygon $ A_1A_2 \ldots A_n$ with area $ S$ and a point $ M$ in the same plane, determine the area of polygon $ M_1M_2 \ldots M_n,$ where $ M_i$ is the image of $ M$ under rotation $ R^{\alpha}_{A_i}$ around $ A_i$ by $ \alpha_i, i = 1, 2, \ldots, n.$
Problem
Source: IMO Shortlist 1989, Problem 18, ILL 62
Tags: geometry, algebra, convex polygon, area, IMO Shortlist