"Adjacent" and "Opposite" sides can change, depending on which angle you start from.

"Cos(x)" means "the cosine of x degrees"; it does NOT mean multiply the cosine by x.

**Study and practice**

- Study introductory trigonometryMathsisfun.com has written a good introductory lesson on trigonometry, which includes definitions, graphics and manipulatives. You don't need to read the whole page - only up to "Unit Circles".
- Quiz yourself on calculating sine, cosine and tangentUse this six-question quiz from onlinemathlearning.com for a quick online check of your trig knowledge.