Radial Dimension
Create and edit the radius/diameter dimension of an arc, circle, or the curvature of a NURBS curve, given a center and a point.
- On the ribbon, click the Drawing tab.
 - 
                Click the Radial Dimension icon.

 - Select an arc or circle.
 - Click to place the dimension.
 - 
                Select a dimension style in the Control Panel.
                
- Leader: Choose from None, Arrow, Circle, Dot, Slash, < >, or Triangle.
 
 - Right-click and mouse through the check mark to exit, or double-right-click.