This is a complete lesson plan introducing the cosine ratio and guiding students to find the length of a side of a right triangle using cosine. The inverse cosine ratio is also covered.
This lesson follows my lesson plans "Introduction to Trigonometry" and "Sine Lesson Plan" which are also posted in my TpT Store.
I also have lesson plans on the sine and tangent ratios posted. If you prefer to teach the three ratios in one lesson, I have the lesson "Sine, Cosine & Tangent" at:
This lesson includes an opening question, minilesson with guided steps through the process, examples, class activities and a worksheet for homework. Answer keys included.
Common Core Standards included on cover page for High School: Geometry
NOTE: You may need Equation Editor or MathType to make changes to some of the fractions or symbols.