C+ is a pass so that is okay, it is okay to fail too, the only important thing is whether you enjoy the subject.
Trigonometry isn't taught right, there is a lot which teachers miss out perhaps because no-one (except me) understands it e.g. they dive into Pythagoras Theorem and tell you to remember equations when there is no need to learn about trigonometric functions, at least not until you can work out the length and angles of triangles yourself the slow way.
Geometry is quite a challenging subject in School,especially Pre-AP Geometry to get into Computer Science.The road can be bumpy and you may stop a few times to get it and if you do,try your hardest to study and remember patterns.I would say to myself, STUDY THE NOTES EVERYDAY because if you get into the habit,you can achieve greatness.
Obviously math is not for you. Better look into something else, or prepare for a life of homelessness and eating raw disease infested garbage while giving blow jobs to fat hairy men with lice and AIDS. This is your future Noah, better get used to it. It's almost unavoidable I'm afraid.
A C+ is considered a passing grade, but if you could be doing better (which I believe to be true) than you're not trying hard enough.
My school considers any grade below a 90% to be failing.
I pass all of my classes; it's actually not that hard, once you get into the groove of studying.
So, I guess that's my tip; study every day.
You can go over past assignments, and work through problems you missed. That's what quizzes are for, too-- to help you gauge what you're studying for.
Granted you can pass the subject. Perhaps you are not trying to become good at math and have your sights on some other field in which case I'd try to do better but not worry so much about it. But if you want to get into a math field or even a science or engineering field I would double down and study. Drill yourself on the subject every night. And if you can start doing better, getting at least Bs in the class start introducing yourself to other aspects of mathematics early, so you have an advantage when you start those subjects later. I also subject paying special attention to mathematical vocabulary (such as matrix, vector, Abelian, space, topology,...) even if you don't have the time to practice the concepts it's associated with yet.
Some people will just dismissively say math is not for you, but if you really want to be good at math you can. It could be that in your case you will have to put in more hours at least until you gain the momentum you need, but there is no reason you can't do that if you want. You may have to cut back substantially on other activities though.