I haven't been able to really jump in and start to study geometry and trigonometry yet, as i haven't been able to find a good textbook. I went to my university's (i am a staff attorney at a local university's legal clinic) bookstore, and looked for a textbook. Sadly, I could only find a single textbook on math, and it was a "pre-calculus" textbook. It just didn't feel like it was what i was looking for.
I think the best plan would be to go to the used bookstores near universities (there is a great Powell's near the UofC) and look for some text books there. (Yeah yeah, any excuse to go to a used bookstore!).
But fear not gentle readers, i have not been complete idle when it comes to learning mathematics. A few years ago, i had a similar urge of trying to shore up knowledge, and bought a cute book called, "A very short introduction to mathematics."
Look at how cute!
Obviously, it is not a textbook, and it literally treats broad fields like cartesian geometry in paragraphs, and limits in sentences. But, reading this little bad boy i think i have started to understand some things that have long bugged me about math. I finally get the reason why 1.9999999 (repeating) is = to 2. And i think i understand the concept of pi a bit better, as well as the notion of irrational numbers.
I got a thrill at the idea that I was starting to understand a very abstract concept, in a real way. I am hoping that this project will continue to bring more of these thrills.