Phi appears in a number of geometric constructions using circles. There are a number of geometric constructions using a circle which produce phi relationships, as described below. Among mathematicians, there’s a bit of a competition to see how few lines can be used to create a phi proportion, or golden section, in the construction, or …
Golden ratios appears in many geometric constructions, including triangles and squares in circles, the pentagon and also in solids such as the dodecahedron.