Ok so I've been adding relations between different lines in different sketches for quite some time now and this is the first time that I've run across this predicament. I am trying to make Line 1 (in the pictures I've provided) the same length as Line 1 @ sketch 9. However I am not able to do so as shown by the picture. I can however add a relation between Line 1 and Line 7 @ sketch 1. Please help me out. I'm confused pretty badly and I realize that I could just take the dimension from the line I want and enter it in for Line 1 but I need to figure this out.

Thanks in advance!