Instead of clicking to define the radius, you can a type values on the Circle command bar. You can also use a combination of graphic and command bar input.

IntelliSketch places relationship handles.

You can use the options on the Circle command bar and the commands on the shortcut menu to edit a circle.

The IntelliSketch command supports horizontal and vertical alignment for the center points of circles. When you place a circle and the center point input recognizes a horizontal or vertical alignment with the center point of another circle, the horizontal or vertical alignment relationship is applied.