This is an exploration activity that leads students to deriving trig functions. Students start by drawing different triangles, measuring angles, and then comparing side length ratios to sin, cos, and tan of the angle. Practice problems are included. I used this in my Math Models class and it was good practice of using a protractor and using Pythagorean Theorem. I really like that the students could follow through the worksheet to find trig ratios without the teacher having to walk them through step by step. This is very student centered.