You can dimension the points relative to other sketch
objects.
Click to set the circle's diameter.
The circle will snap to existing sketches or determined circles and arcs in
the plane of the sketch.
If you sketch two circles that are tangent to
each other, and then change the diameter of one circle by editing its
dimension, tangency with the other circle is maintained.
If you drag
the center of a circle that is tangent to another circle, the radius of the
other circle changes to maintain tangency.
