- circumcircle
- regular polygons-1
- inscribed quadrilaterals
- an archimedes' formula
- simson line
- regular polygons
- sum of the interior angles of a n-gon
- an equilateral triangle
- the flower of life
- Johnson's theorem
- miquel's triangle theorem
- Brahmagupta's formula
- exeter point
- properties of the altitudes
- approximating pi-1
- circles of a regular n-gon
- regular polygons-3
