Refuse the assignment. The way the libs have pushed the metric system is that it is easier because it is based on 10s. Dividing metric measurments int 6ths and 8ths is so asinine it must come from public educators.
I have to disagree with you here. The metric system is far superior - and makes sense. The lobs have nothing to do with it. It’s been in use in sciences for nearly 200 years because it just works better. Now we could talk about the problem of 60 seconds in a minute, but that’s already been a standard since the Babylonians or Sumerians or whomever decided it, but there is no reason to be counting base-12 at all. The big problem with is question is that no one would ever divide a meter into 8 segments, it would always be base-10, so 4/6 and 5/8 doesn’t necessarily exist in practical use of the metric system. The question is should refer to each as base-10, ie; 5/10 and 6/10, then it all becomes clear, and that is why the metric system works so well. Common denominators should be apied here, but the OP did say that was a follow up lesson, so perhaps this question was meant to be misleading on purpose. Regardless, its a horrible question to ask in hopes of furthering a student’s understanding of real numbers. This should have at least had the lines and segments the same length.