This has been bugging me in the back of my head about for more than 5 years now.

It started with me seeing a meme about if you want to fairly cut a cake for 5 people with only 3 cuts you just have to kill a guy and cut the cake 1/4. Got me interested in the actual riddle and I've proved it's narrowly impossible.

I tried it for other shapes, but I pentagons and hexagons were just too complicated for pen and paper. I got the answer for general triangles but I forgot about it now.

I did google this for like an hour and nothing useful came out. Do any of you know this problem and what are some interesting theorems?