In fact, circles and circular arcs are ellipses and elliptic arcs. When being created, they are set to be the circular special cases; but, they do not differ from elliptic objects in anything more significant then just a few property values. Therefore, circles have two radii and other properties which might seem useless.
See Elliptic arcs for full description.
• Circular arc defined by three points on its perimeter
Creates a circular arc defined by three points on its perimeter. The three points must not be collinear.
• Circular arc defined by the center point and radius
Creates a circular arc defined by the center point and radius. The radius, the end point parameters, etc. can be modified in the Property editor.
• Circle defined by three points on its perimeter
Creates a circle defined by three points on its perimeter. The three points must not be collinear.
• Circle by the center point and a point
Creates a circle defined by the center point and a point on its perimeter.
• Circle by the center point and radius
Creates a circle defined by the center point and radius. The radius can be modified in the Property editor.