Other Definitions
heptagon (dict)
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HeptagonA heptagon is a plane figure with seven sides and seven angles. In a regular heptagon, in which all sides and all angles are equal, the sides meet at an angle of approximately 128.6 degrees. Its Schlfli symbol is {7}. The area of a regular heptagon of side length a is given by -
A regular heptagon is not constructible with straightedge and compass. The United Kingdom currently (2003) has two heptagonal coins, the 50p and 20p pieces. Strictly, the shape of the coins is a curvilinear heptagon: the sides are curved outwards so that the coin will roll smoothly in vending machines. The heptagon is also commonly referred to as the septagon as the sept- prefix indicates seven in Latin, in contrast to hept-, which is Greek. See also
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