Basic Trigonometry (videos)
Basic Trigonometry (videos) from Khan Academy
The link address is: http://www.khanacademy.org/math/trigonometry/basic-trigonometry/basic_trig_ratios/v/basic-trigonometry
The link address is: http://www.khanacademy.org/math/trigonometry/basic-trigonometry/basic_trig_ratios/v/basic-trigonometry