The following automenu option of the 
 Axis command can be used for creating simultaneously either horizontal and vertical axes of a circle/circular arc, or major and minor axes of an ellipse/elliptical arc:
  | 
<2>  | 
Two Axes of Circle or Ellipse  | 
To do this, just select a graphic line of a circle, ellipse or arc. The axes are created automatically upon selection of a source line, without requiring the confirmation.
The limits of the axes are defined by the radii of the selected elements.
   
   
See Also:
•Axis