We want to approximate . We know that the circumference C and diameter d of any circle are related by the formula C-d. Thus, it is convenient to start with a circle of diameter 1, and in this case C = . The idea is to approximate the circle by using inscribed and circumscribed (regular) polygons 2 sides, each of length 2" sides, each of length 2 inscribed octagon circumscribed octagon Perimeter of inscribed 2"-gon circle of diameter 1 and circle of diameter l Perimeter of circumscribed 2.gon Circumference and circumference FIGURE 1. Inscribed and circum scribed octagons Figure 2. Inscribed and circumscribed 2"-gon:s We want to approximate . We know that the circumference C and diameter d of any circle are related by the formula C-d. Thus, it is convenient to start with a circle of diameter 1, and in this case C = . The idea is to approximate the circle by using inscribed and circumscribed (regular) polygons 2 sides, each of length 2" sides, each of length 2 inscribed octagon circumscribed octagon Perimeter of inscribed 2"-gon circle of diameter 1 and circle of diameter l Perimeter of circumscribed 2.gon Circumference and circumference FIGURE 1. Inscribed and circum scribed octagons Figure 2. Inscribed and circumscribed 2"-gon:s