The 47th problem of Euclid is show at the left and is where Pythagorean theorem comes from. Star Trek Voyager used lots of 47's in dialog or numbers shown whenever they could. There are lots of websites and you tube videos that show examples and explain about the college that this came from and how the producers did this as a joke. I have not seen anyone show Chakotay or Janeway doing the 47 triad with their hands or that Chakotay's tattoo looks like Roman Numerals for 3, 4 and 5 as a nod to 47th problem. I think the actors did what they were told. I am not implying they are Masons. I just think this show more 47 placement
Also the tattoo is over his eye to mark as Horus and they had him hookup with the other Horus of the crew in Seven of Nine. Maybe they were thinking 4+4 = 8 so 7, 8, 9.