Select Measure → Entity Info and click any entity, or enter the entity reference in the Show Coordinates panel to display full property data.
Two ways to view entity information: 1) Measure → Entity Info — click any entity to display a full property panel. 2) Show Coordinates panel — enter an entity reference (e.g. A3) to display its full coordinate and property data.
For an arc, Entity Info displays: type, ccw, centre, radius, diameter, start_point, end_point, start_angle, end_angle, sweep_degrees, and length.