In the plane of any triangle ABC, let
A'BC = the equilateral triangle shown on side BC,
The lines AA', BB', CC' meet in the |

The Fermat point is also known as the *1st isogonic center*, the roots *iso* and *gon* meaning *equal-angle*. This is because the angles BFC, CFA, AFB are all equal. (The *2nd isogonic center* is obtained using the *other* three equilateral triangles on the sides of triangle ABC.