Equilateral pentagon Equilateral pentagon In geometry an equilateral pentagon is a polygon with five sides of equal length. Its five internal angles, in turn, can take a range of sets of values, thus permitting it to form a family of pentagons. The requirement is that all angles must add up to 540 degrees and must be between 0 and 360 degrees but not equal to 180 degrees. In contrast, the regular pentagon is unique, because it is equilateral and moreover it is equiangular (its five angles are equal; the measure is 108 degrees). Four intersecting equal circles arranged in a closed chain
The Pentagon project for the U.S. Army. The Pentagon is the world's largest office building, with about of space, of which are used as offices. Some 23,000 military and civilian employees, and another 3,000 non-defense support personnel, work in the Pentagon. It has five sides, five floors above ground, two basement levels, and five ring corridors per floor with a total of of corridors. The central five-acre (20,000 m) pentagonal plaza is nicknamed "ground zero" on the presumption that it would be a prime target in a nuclear war. On September 11, 2001, exactly 60 years after the building's construction began, American