Module 4: Foundations of Trigonometry

 

Refresher

 

Review in which quadrants the trigonometric ratios are positive or negative and the CAST rule in Trigonometric Ratios in All Four Quadrants.

 

The CAST Rule can be used to help remember signs of the different ratios for each quadrant. This rule is based on the signs of the coordinates in each quadrant.

This is a play button that opens Finding Angles from a Point on the Terminal Arm.

Review Finding Angles from a Point on the Terminal Arm. This example outlines how to determine trigonometric ratios given a point on a terminal arm.


This is a play button that opens Finding Angles from a Point on the Terminal Arm.

Review Formal Definitions for Primary Trigonometric Ratios. This outlines how to express trigonometric ratios in terms of x, y, and r.

This is a play button that opens Using a 30-60-90 Triangle for a 150-degree Angle.

Watch Using a 30-60-90 Triangle for a 150° Angle. This example outlines how to determine the exact value of a trigonometric ratio using reference triangles.


This is a play button that opens Using a 30-60-90 Triangle for a 300-degree Angle.

Watch Using a 30-60-90 Triangle for a 300° Angle. This example outlines how to determine the exact value of a trigonometric ratio using reference triangles.



Go back to the Are You Ready? section and try the questions again. If you are still having difficulty, contact your teacher.