Lesson Materials

Lesson 7-4: Special Angles

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The student will be able to evaluate the sine, cosine, tangent, secant, cosecant and cotangent of any angle whose reference angle is 0°, 30°, 45°, 60° or 90°.

  1. In the applet to the left, drag the red button to set the angle to 30°.

  2. What is the radius of the circle that is shown? This radius is also the hypotenuse of the right triangle!

  3. Look at the measure of the legs of the triangle, the trig ratios are shown for these measures. Do you recognize any of these numbers?

  4. Drag the red button to set the angle to 45° and 60°. Check the measures and trig ratios for these angles too.

No hands-on yet

The Math Page: Online notes on 30-60-90 triangles and their corresponding trig values. The Math Page
Interactive Math: Online notes on 30-60-90 & 45-45-90 triangles and their corresponding trig values. Interactive Math
Interactive Math 2: Online notes on the signs of the trig functions in each quadrant. Interactive Math 2

Click the buttons to open the following puzzles. The puzzles will likely open in a window behind this one.

  1. SINE Puzzle (Click Button)
  2. COSINE Puzzle (Click Button)
  3. TANGENT Puzzle (Click Button)
  4. MIXED Puzzle (Click Button)