The circle or arc tangent commands can do "tangent to 3 curves", "tangent to 2 curves through a point", or "tangent to 2 curves with a specified radius".

But in your case here you don't want any those, you want "tangent to one curve through a point with a specified radius".

So the circle or arc tangent commands won't help for this case but this type of "specified radius through a point" problem can be solved by some construction geometry, you first set up a circle of the target radius centered on the point.

- Michael