A Stable One - Dimensional Table

In the Columbia Teachers College/COMAP Mathematical Modeling Handbook, one of the modules, "Stable Table," concerns this topic: If a typical four-legged table on a continuous but irregular floor has only three legs that are on the floor, it is not necessary to use a folded napkin or other prop to stabilize it. You can rotate the table, and there will be a stable position within a rotation of at most 90∞-stable, but not necessarily horizontal.