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 of the Pentagon damaged in the attacks, and the side of the building is illuminated at night with blue lights. After the attacks, plans were developed for an outdoor memorial, with construction underway in 2006. This Pentagon Memorial consists of a park on of land, containing 184 benches, one dedicated to each victim. The benches are aligned along the line of Flight 77 according to the victims' ages, from 3 to 71. The park opened to the public on September 11, 2008. On the building's main concourse is the Hall of Heroes, opened 1968 and dedicated to the more than