Equilateral pentagon of δ can be seen from the figure: Simplifying, δ is obtained as function of α and β: The remaining angles of the pentagon can be found geometrically: The remaining angles of the orange and blue triangles are readily found by noting that two angles of an isosceles triangle are equal while all three angles sum to 180°. Then formula_7 and the two remaining angles of the green triangle can be found from four equations stating that the sum of the angles of the pentagon is 540°, the sum of the angles of the green triangle is 180°, the angle
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