This trigonometry lesson introduces important trigonometry topics including the Pythagorean theorem, special right triangles, trigonometric functions, the law of cosines and sines, identities, and half and double angle formulas. Key concepts are the measurement of triangles, trigonometric ratios related to sides of right triangles, and trigonometric functions defined in relation to angles. Examples are provided to demonstrate applying the Pythagorean theorem and laws of cosines and sines to solve for unknown sides of triangles.

1. Trigonometry Lesson Two: Introduction to Trigonometry The Basics

9. The Unit Circle