Rotate Object in AutoCAD by a Specific Angle

Question
How do I rotate an object in AutoCAD by a specific angle?

Answer
To rotate an object(s) about a point and along a line, type RO (for rotate) enter, select what you want to rotate, pick your base point. The command line now prompts you for an angle or copy/reference, type r for reference and then pick the same base point as your first point, enter, select a second point which will be the other end of your object(s), finally select the point that you want to rotate to. Job done.