# Hypocycloid

- Author:
- Przemysław Kajetanowicz

When a circle of radius rolls inside a circle of radius , then a fixed point on the rolling circle
traces a curve called a (the resulting curve is a segment of a straight line);
(the resulting curve is called a deltoid);
(the resulting curve is called an asteroid).

*hypocycloid*. Experment with the interactive illustration below. In particular, study the special cases: