I've struggled with this problem for years...
When creating circles using tan/tan/raduis method the circle often does not intersect with the object selected. I know this only happens when my drawing coordinates are big (around X=400,000 Y=6,400,000 from the origin) an is due to Autocads methods of handling big numbers.
What I wat to know is if there is a way of overcoming this without moving my objects closer to the origin. My coordinates are important as they relate to a horizontal datum.
I tried the UCS command and set an origin close to me objects. This had no effect.