In Section 5-25 of the manual, we find that lengths of proportioned lines are comparable only when reduced to their cardinal equivalents. Essentially, this is just what we did in the single proportionate problem. We broke the lines down into their true cardinal equivalents. So, let's approach four-way measure the same way.

Let's simplify by considering one line at a time. For example, let's take the north/south or the meridional line first. Notice that for retracement, we now show only the cardinal equivalents in latitude. The departures are not needed at this time

Total the half mile increments of the record . . .

. . . and then total the half mile increment of the retracement.