I have a very strange problem that has me scratching my head. All of a sudden, when I use the line segment tool to create a line that is 1" long (by clicking and entering the segment length not by clicking and dragging), it creates a line about 6" long. It even tells me that the line is 1" long in the properties panel when I can clearly see that it is not. Additionally, when I hold shift to constrain the angles my lines are snapping to odd angles, not the traditional 0,90,180 degrees etc. When I create a line with the pen tool I can make a line the appropriate length. And side by side illustrator is telling me that both of these lines are 1" long when clearly the line drawn with the pen tool is exceptionally longer.