After selected the Create Arc Area option from the right-click menu,
the Specify Range of Arc (below) dialog will populate. In this dialog
you can specify the range for the Arc Area, the Start and Swept Angle
and choose the option to Manually Draw Extents of Arc or Draw Arc at Fixed
Radius from Center point.
Once you hit 'OK' the Digitizer cursor will be renamed to 'Area'. Left-click and hold the left mouse button at the center of the feature, then drag it until the new area feature is of the desired shape. Once the shape is finished, release the left mouse button and the Modify Feature Info dialog will appear allowing you to setup the label, classification, drawing style, and attribution for the new feature. See Editing Feature Attributes and Drawing Styles for more details.
Once the shape is completed, the Digitizer Tool will remain in the selected shape creation mode. Left click to start drawing a new shape, or right-click to choose a different mode.