Choose RadTanTan.
Width of donut <value>: Enter the width of the donut, or specify two points. (The width of a donut is the area between the inside and outside diameters.)
Diameter of donut <value>: Enter the diameter, or specify a point. (If you specify a point for the radius, you are prompted to specify a second point.)
Select first tangent point: Select the first entity that you want the donut to touch.
Select second tangent point: Select the second entity that you want the donut to touch.