Protractor measures the angle between a point and any two objects in your scene.
The names of the two objects appear above their respective buttons, and the angle formed at the protractor object between the pivot points of the two objects is displayed in the Angle field. Lines are drawn between the protractor and the two selected objects.
Colors panel
Elements drop-down list
Gizmos group. The Protractor color is set by choosing the Tape Object in Customize User Interface dialog
Colors panel
Elements drop-down list
Objects group.
You can reselect the protractor at any time, enter the Modify panel, and pick new objects to measure. You can move either of the two objects or the protractor itself to change the angle.
If you need to watch the Angle readout while moving either of the objects, first select the protractor, then click the Pin
Stack button on the Modify panel. You can now select and move the other objects while the stack remains pinned to display
the protractor angle.
Helpers section, click in the viewport to place and create the protractor icon. You can also drag to move it before releasing
the mouse button.
The Angle parameter shows the angle formed by lines from the protractor object to the two picked objects.