ortho or polar tracking angle

Is it possible to match the ortho angle or the polar tracking angle exactly to an existing line, in the same manner as using the rotate command with the Reference mode? The polar tracking angle can be set to any desired numerical value, by entering the angle manually from the diaglog box. Similarly, the grid orientation can be set to any desired angle, and then with the ORTHO mode on, the cursor is constrained to move at that angle and 90 degrees from it. But I have not found a way to constrain the cursor to move at the angle of an existing line. I could leave the ORTHO angle set to zero, then draw the desired lines horizontal and vertical, and then rotate all of those lines to match an existing line by using the rotate command with the Reference mode; but that seem like a clumsy way to do it. Autodesk Generic CADD has a "like" function that can be used to set any of many parameter values, including ortho angle, to match existing objects. Is there anything like that in AutoCAD? If not, any other suggestions? Dick Alvarez alvarez at alumni dot caltech dot edu