This task shows how to create a bitangent line by creating two tangents (on two different elements).  
Create two circles.  




The bitangent line appears between both selected elements. The bitangent line appears as well as the corresponding constraints provided you activated Geometrical Constraints . 

Tangents are created as close as possible to where you clicked on the circle.  
At this step, create a point.  
At any time, you can select a point type element. The line will go through this point and a coincidence constraint is created on this point.  
