The default right mouse button option, Select pairs, allows you to select two circles or circular arcs. The Equal Radius constraint will ensure that circles or circular arcs have the same radius. Then, by placing a radius or diameter dimension on one of the arcs or circles, you can control the radius of all of them. The right mouse button option, Select multiple, allows you to select a continuing series of circles, and circular arcs. In the series, after you have selected two edges, a constraint is created and then the second edge you selected is used as the first edge for the next pair. This continues until you either use the right mouse button to start a new series or return to standard pairs selection. You can preselect a series of circles and circular arcs before selecting the function and they are treated like a series selected in 'Select multiple' mode.