Visual Trig Values

Up to 90°

On this first applet, control the angle to see how the red, green and blue lines get longer or shorter.

  1. At what angle do the green and red line segments have equal length?
  2. Given that the angle permitted ranges from zero to 90°, whats the shortest/longest green line segment?
  3. What’s the shortest/longest red line segment?
  4. What’s the shortest/longest blue line segment?
  5. How many right angled triangles are there in the diagram?
  6. What does Pythagoras’ theorem say about those right angled triangle(s)?

Matching to 90°

  • Level 1 – use the applet with values
  • Level 2 – use the applet without values
  • Level 3 – visualize the applet with the mind’s eye

0 to 360 degrees

However sine, cosine and tangent are defined for any angle – from negative infinity to positive infinity. Here we see the value of sine, cosine and tangent for angles between 0° and 360°.

Matching, 0 – 360

Once again, by considering the visual above, match the labels with their values:


2. Trigonometry Menu

Next: Estimating Angles and Sides