這些正多邊形具有相同的外接圓，所以當邊數愈多時，其周長會愈接近外接圓的圓周長。由於圓周率定義為「圓周長與直徑的比值」，因此利用正多邊形的周長／直徑作為近似值，便能得到愈來愈接近 π 的結果。 Since all of these regular polygons share the same circumcircle, their perimeters become closer and closer to the circumference of the circle as the number of sides increases. Since π is defined as the ratio of a circle's circumference to its diameter, the ratio of the polygon's perimeter to the circle's diameter provides an increasingly accurate approximation of π. (Translated using Google Translate)
