(I know this is a joke, but I have a related real story ...)<p>One of my friends had a problem a few years ago because she had a compass in the carry on luggage. It has a sharp metal tip, so it&#x27;s forbidden. She didn&#x27;t have any problem, and she could put it in the main luggage.<p>I think he protractors are completely safe, at lest the plastic protractors ...