How to learn Trigonometry!

If you would like to learn a bit about trigonometry, or brush up on it, then read on. These notes are more of an introduction and guide than a full course. For a full course you should take a class or at least read a book.
There are no grades and no tests for you to take, and no transcripts and no awards. There are a few exercises for you to work on. The exercises are the most important aspect of a trigonometry course, or any course in mathematics for that matter.
You should already be familiar with algebra and geometry before learning trigonometry. From algebra, you should be comfortable with manipulating algebraic expressions and solving equations. From geometry, you should know about similar triangles, the Pythagorean theorem, and a few other things, but not a great deal.
Trigonometry is like other mathematics. Take your time. Write things down. Draw figures.
Work out the exercises. There aren't many, so do them all. There are hints if you need them. There are short answers given, too, so you can check to see that you did it right. But remember, the answers are not the goal of doing the exercises. The reason you're doing the exercises is to learn trigonometry. Knowing how to get the answer is your goal.