Bottema's theorem is a theorem in plane geometry by the Dutch mathematician (Groningen, 1901–1992). The theorem can be stated as follows: in any given triangle , construct squares on any two adjacent sides, for example and . The midpoint of the line segment that connects the vertices of the squares opposite the common vertex, , of the two sides of the triangle is independent of the location of . The theorem is true when the squares are constructed in one of the following ways: If the squares are replaced by regular polygons of the same type, then a generalized Bottema theorem is obtained: