Geometry is very fiddly math. There were a lot of proofs and the like. (Maybe that’s different now in High School.) A lot of it ends up reducing to a few things you’ll use over and over and over. Geometry is really more about why these things work instead of the game it starts out seeming like it is. There are all sorts of applications to trigonometry (which is really a part of geometry that’s big enough to deserve its own class) that you’re not going to see until you’re doing much more math or engineering or any of the physical sciences or 3D graphics work or… any number of things.
I think the best approach to taking geometry is to see it as a game you’re going to try to win each day and trust that it’ll be useful later. Try to notice what’s happening over and over so you can rely on it later on. Some things build on the last thing and are more important, and some things they’re filling time with and don’t matter a lot. Make it a game and have fun with it.
Others have already told you what sine, cosine, and tangent are. So, I won’t repeat.
Cheers!
Cyndy