Calabi's Triangle
The one Triangle in addition to the Equilateral Triangle for which the largest inscribed Squarecan be inscribed in three different ways. The ratio of the sides to that of the base is given by 
(Sloane's A046095), where
is the largest Positive Root of
which has A046096).See also Graham's Biggest Little Hexagon
References
Conway, J. H. and Guy, R. K. ``Calabi's Triangle.'' In The Book of Numbers. New York: Springer-Verlag, p. 206, 1996. Sloane, N. J. A.A046095 andA046096 in ``An On-Line Version of the Encyclopedia of Integer Sequences.''http://www.research.att.com/~njas/sequences/eisonline.html.
- Coin
- Coincidence
- Coin Flipping
- Coin Paradox
- Coin Problem
- Coin Tossing
- Colatitude
- Colinear
- Collatz Problem
- Collinear
- Super-3 Number
- Superabundant Number
- Super Catalan Number
- Superegg
- Superellipse
- Superfactorial
- Supergraph
- Supernormal
- Superperfect Number
- Superposition Principle
- Super-Poulet Number
- Superregular Graph
- Superscript
- Superset
- Supplementary Angle