Lesson 1

Lesson 1 Summary

When determining distances or angles in real-world problems, you often end up with diagrams that contain two right triangles that share a side. You can often use the primary trigonometric ratios to solve for the shared side in the first triangle; then use that side length to solve for a side or angle in the second triangle.

Remember that “primary trigonometric ratios” is the fancy way of referring to the following equations:

In the next lesson you will learn about trigonometry for oblique triangles (i.e., triangles that do not contain a 90° angle).