1- the BASICS of TRIGONOMETRY
http://www.youtube.com/watch?feature...&v=T8B8Tcz8kog
2- Learn trigonometry in 19 minutes
http://www.youtube.com/watch?v=AjSPr...eature=related
3- Right Triangles Inscribed in Circles (Proof)
http://www.youtube.com/watch?v=b0U1N...feature=relmfu
4 - murrey math lines / indicator
5 - Mathematics Gives You Wings
http://www.youtube.com/watch?v=LSxqpaCCPvY