Rotate without distorting size I'm trying to create a 45 degree angle on a specific sized rectangle. However, when I rotate my end vertices, the size of the rectangle also changes.

How can I rotate without changing the size of my object?

The object on the left is what I am trying to acomplish. The object on the right is what happens if I rotate the two vertices to a 45 degree angle.
The command you are looking for is called SHEAR. Select the vertices you want to rotate and press Space and type in "shear" (or ShiftCtrlAltS at the same time)