Just looking for techniques here. My parallel ruler is 12 inches long. If two points on the chart are separated by more than 12 inches, what is the best way to accurately connect them for a course line, especially for the final exam? Should I bring a couple of straight edges? Get an eighteen inch or longer ruler? Fold the side of the chart over and use that for a straight edge? The worst case would be going from one edge of the chart to another, and the chart is 45 inches wide. I do understand the concept of walking the parallel ruler, but that assumes I have a line to follow, and, in this case, I'm trying to establish a line, not follow one. Thanks for the advice!
You can use all of those techniques but the easiest one would to simply use a ling straightedge. This would be especially true when taking your final proctored exam.