Squaring the Circle: onscribed polygons

The book is about the number pi and squaring the circle. The book is about regular polygons placed on the circle. They are called onscribed regular polygons. Archimedes used inscribed and circumscribed regular polygons for a given circle. He approximated the circumference of the circle and by this he was able to estimate the number pi. The presented here onscribed  regular polygons are more accurate for this approximation. The presented material is illustrated.It is a good tool for teaching mathematics.