Collection of the math notes, in this case on basic Trigonometry. Lovely site in general for refreshing or even learning some HS level math!

Touch Trigonometry is a simple Flash gizmo (written entirely in ActionScript 3.0) that hopes to help math learners of all ages get an intuitive understanding of trigonometry. It aims to do that by letting you just play with the trig functions, with no buttons to get in the way.