SOLUTION: a circle is inscribed in a equilateral triangle,its radius is 4,how to find its side?

Draw OB perpendicular to the bottom side at B.

Radius OA bisects 60° angle at A, so angle OAB = 30° 

AB is half the side.  OA is a radius = 4.







   <-- half a side

, approximately 6.92820323

Edwin