# Lesson Plan: Right Triangle Trigonometry: Solving for a Side Mathematics • Third Year of Preparatory School

This lesson plan includes the objectives, prerequisites, and exclusions of the lesson teaching students how to find the value of a missing side length in a right triangle by choosing the appropriate trigonometric ratio for a given angle.

#### Objectives

Students will be able to

- label the sides and angle of a right triangle,
- find a missing side length in a right triangle (given a figure) using the sine, cosine, and tangent ratios where the unknown is at the
**top**of the ratio, - find a missing side length in a right triangle (given a figure) using the sine, cosine, and tangent ratios where the unknown is at the
**bottom**of the ratio, - find all the lengths of a right triangle,
- draw a figure for a question and use it to find unknown lengths,
- interpret and solve real-life and applied problems to find unknown lengths using right triangle trigonometry.

#### Prerequisites

Students should already be familiar with

- the sum of interior angles in a polygon,
- properties of polygons,
- similar and congruent triangle properties,
- right triangles and the Pythagorean theorem.

#### Exclusions

Students will not cover

- solving for an angle using trigonometry,
- non-right triangle trigonometry,
- angles of elevation and depression.