The angle tool displays a movable arc on the graph view. (See below:)
This arc measures angles on your graph in degrees, radians and multiples of pi, independent of the 'x' and 'y' scales.
Select the angle tool by clicking the button on the graph tools tool bar, or by selecting the 'Angle' command from the 'Tools' menu.
When selected, the angle tool dialog box is displayed. (See below:)
Changing the arc angle:
Rotating the arc:
Changing the length of the arc lines: