Autodesk AUTOCAD 2006 Command Reference Manual page 416

Polar Tracking On
Turns polar tracking on and off. You can also turn polar tracking on or off by
pressing F10 or by using the AUTOSNAP system variable.
Polar Angle Settings
Sets the alignment angles for polar tracking. (POLARANG system variable)
Increment Angle
Sets the polar increment angle used to display polar tracking alignment
paths. You can enter any angle, or select a common angle of 90, 45, 30,
22.5, 18, 15, 10, or 5 degrees from the list. (POLARANG system variable)
Additional Angles
Makes any additional angles in the list available for polar tracking. The
Additional Angles check box is also controlled by the POLARMODE system
variable, and the list of additional angles is also controlled by the
POLARADDANG system variable.
NOTE Additional angles are absolute, not incremental.
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