This is the first in a series of major trigonometry topics, adapted from a series of lessons that I wrote for homeschoolers. It is the foundation for the rest of the series. It includes the trigonometric functions in a right triangle and how to use them as well as introducing the first identities of trigonometry. This is a very orderly presentation that builds from idea to the next. Step-by-step examples and problem solutions. Can be 2 or 3 lessons.Download the preview to see suggestions and complete content for this product.