Polygons and circles
Squares, hexagons, pentagons, a clock face, and tangents.
- Square on a segment A perpendicular at B, then equal circles
- Regular hexagon The radius steps around the circle six times
- Square inscribed in a circle Two perpendicular diameters
- Regular pentagon (Ptolemy) Golden section of the radius gives the side
- Regular pentagon (Richmond) Bisect an angle at the middle of a radius
- Clock hours (regular 12-gon) Hexagons from two perpendicular diameters
- Tangents from a point The circle on OP as diameter meets the circle at the touching points