Sorry, Stillblue, I didn't explain well. I didn't mean it only works on closed paths, simply that I test-measured individual line segments on triangular closed paths because that would be a stiffer challenge, and rotating the copied individual line segments and rotating them to perfectly vertical or horizontal was simply to check my original measure on the closed path segment. Once you have the straight vertical or horizontal line, the info window gives you a very accurate measure of the line's length and, as I indicated, I've never seen the measure tool on an angled line be out by more than 1/1000 of a point from the info window's measurement of the same line rotated to square. I like it because I hate creating needless work for myself.