Sketcher > Constraining Geometry > To Obtain Information about a Constraint
  
To Obtain Information about a Constraint
1. Do one of the following operations:
Select a constraint symbol in the Sketcher window, and then right-click and choose Explain from the shortcut menu.
Click Sketch > Constrain > Explain, and then select a constraint symbol in the graphics window.
An explanation appears in the message area and the constrained entities are highlighted in a different color.