Khan Academy
Khan Academy: Geometry: Complementary and Supplementary Angles
Defines and gives examples of complementary angles, supplementary angles, and adjacent angles. Practice problems available. [8:31]
Khan Academy
Khan Academy: Angles: Complementary and Supplementary Angles
Basics of complementary, supplementary, adjacent and straight angles. Also touching on what it means to be perpendicular.
PatrickJMT
Patrick Jmt: The Law of Cosines
This video provides the formula for the 'Law of Cosines' and one 'applied' example is shown. [4:58]