Area of a circle each polygon side is a radius, of length "r". And since the total side length is greater than the circumference, the polygon consists of "n" identical triangles with total area greater than "T". Again we have a contradiction, so our supposition that "C" might be less than "T" must be wrong as well. Therefore, it must be the case that the area enclosed by the circle is precisely the same as the area of the triangle. This concludes the proof. Following Satō Moshun and Leonardo da Vinci , we can use inscribed regular polygons in a different way. Suppose we
Earth's circumference system of latitude and longitude. Longditude lines, also known as meridian lines, follow the polar circumference, and are all exactly the same length. Latitude lines, known as circles of latitude are parallel to each other; the equatorial circumference is the largest circle of latitude, and the Earth’s longest circumference distance. Other circles of latitude have smaller circumference; for example, the 60th parallel north or south is approximately half as long as the Equator. According to Cleomedes' "On the Circular Motions of the Celestial Bodies", around 240 BC, Eratosthenes, the librarian of the Library of Alexandria, calculated the circumference of the