This tool changes the total length of one line based on the difference in length between two sets of lines.

Select one or more lines to measure. The lines do not have to be connected.

Next, select one or more lines that will be measured and compared to the first set. 

Find the line in the second set that you want to be adjusted. Select one end point on that line for adjustment.

The point you have chosen will move the amount of the difference in measurement between the first set and the second set.