In this module, you can study how to calculate sine, cosine and tangentfor the angles of a right triangle, and how to use "SOH CAH TOA" to remember the formulae for calculating sine, cosine and tangent.
Did you know?
"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.
Mathsisfun.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".