Last modified on 28 May 2011, at 17:33

Trigonometry/Circles and Triangles/Thebault's theorem

Thebault's theorem states that if you take any parallelogram, and construct squares (all pointing outward or all pointing inward) on each side, the centres of the four sides are the four corners of another square.

This theorem was published by Victor Thebault (1882-1960) in 1937.