What is the name of a 99 sided shape?

Answer 1

99-agon

Answer 2

It's quite acceptable to call it a 99-agon but what's more important is knowing how to work out its properties.

Answer 3

I would call it a 99-gon. However, if you wish to annoy your audience (unless they are Greek) or be pretentious, you could call it an enneacontanonagon.