A pentagon is a two-dimensional geometric shape with five straight sides and five angles. The word "pentagon" comes from the Greek words "penta" meaning five and "gon" meaning angle. Pentagons can be regular, where all sides and angles are equal, or irregular, where the sides and angles are of different measures. Regular pentagons possess a unique symmetry and can be found in various natural and man-made structures, including the familiar shape of the Pentagon building, headquarters of the United States Department of Defense.
