As requested on the twitters here is the trig wheel I shared with the folks in the PreCalc morning sessions at #TMC14. I’m going to repeat what I said there; I found this on someone’s blog. I don’t know now who. But I stole it from somewhere. So if it’s yours, tell me and I’ll credit you – and THANKS!
The file (each student needs one circle in each of two colours):
Mark degrees anti clockwise on one circle (make sure you start at the correct line) and radians anticlockwise on the other (note that the numbers should go under the line, it’ll make sense later!):
Cut along the zero line from the edge to the centre:
Place the two wheels so the cuts line up and the labeling faces inwards and slide one circle into the other – this should reveal an angle – rotate until you find what you want and flip over to convert: