The regular hendecagon is the regular polygon with 11 sides, as illustrated above, and has Schläfli symbol {11}. The regular hendecagon cannot be constructed using the classical Greek rules of geometric construction. The rim of the U.S. Susan B. Anthony dollar coin was a regular hendecagon, as illustrated above. The inradius, circumradius, and area of the regular hendecagon with unit side lengths are r = 1/2cot(1/(11)pi) approx 1.70284 (1) R = 1/2csc(1/(11)pi) approx 1.77473 (2) A =...