This shows how the Conchoid can be used to trisect an angle.

Drag point H and watch how the length of IH changes and how the ratio of angle EDF to EDH changes.[br]Under what condition does that ratio become 3?[br]Click the 'Show Conchoid' checkbox. What do you think the three things that define this Conchoid are? (location of pole, which line is the directrix, and what is the 'distance')?