This is a complete lesson plan introducing the tangent ratio and guiding students to find the length of a side of a right triangle using tangent. The inverse tangent ratio is also covered. This lesson follows my lesson plans: "Introduction to Trigonometry," "The Sine Ratio Lesson Plan," and "The Cosine Ratio Lesson Plan," which are also posted in my store.
If you prefer to teach the three ratios in one lesson, I have the lesson "Sine, Cosine & Tangent" posted at:
http://www.teacherspayteac