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Trigonometric Ratios and Reference Angles of General Angles


This applet can be used for classroom demonstration or for student self directed learning or revision

Group Size: Any

Learning Objectives:

At the end of the lesson, students should know how to

  1. determine which quadrant the general angle lies in
2 calculate the reference angle given a general angle 3. determine if the trigonometric ratio of the given general angle is positive or negative 4. determine the appropriate trigonometric ratio (with correct sign), of any given general angle

Guiding Question:

  1. Which quadrant does your general angle lie?
2. What is the reference angle of your given general angle? 3 What can you say about the size of the reference angle, ie. are they acute, obtuse or reflex angles ? (for all cases of general angles) 4. Which axis is always adjacent to the reference angle which is an included angle between that axis and the rotating 'arm' of the general angle? 5. Which are the quadrants where the each of the sine, cosine and tangent trigonometric ratios positive respectively? 6. Can you say in words how the trigonometrical ratios of a general angle is related to the trigonometrical ration of its reference angle?


Applet as provided.


Move the Angle Slider to the left or right. This will decrease or increase the general angle Click on each of the checkboxes to reveal the appropriate attributes eg reference/principal angle, reference triangle, trigonometric ratios, positive trigonometric ratio regions etc.


Not applicable (NA)

Answer Key or Rubric:


Benchmark or Standards:

GCE O Levels

Attached Files: