Here's a video about flat Earthers where the presenter (sarcastically) makes an argument on how to prove the flat Earth theory.
In case that timestamp link doesn't work, the argument begins at 9:13, and since I know @mobbs isn't liking video dumps, I'll sum it up: if the Earth is truly a disc with the center at the North Pole, then the length of any line of latitude "south" of the Equator, such as the Tropic of Capricorn or Antarctic Circle, will be much longer than the Equator.