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Introduction to Trigonometry

Author:Rod Tolle, Alex CHIK, GeoGebra Institute of Hong Kong

  1. Check the boxes to reveal the lengths of the fishing rod and fishing line.
  2. Check the box to reveal the Ratio
  3. Click "Take a Picture"
  4. Change the length of the fishing rod using the RED X
What do you notice about the ratio for 30º ?

  • is called the SINE ratio.
Calculate sin(30) using a calculator:

--------------------------------------------------------- IF you do not get 1/2 or 0.5, ask your teacher for help getting your calculator to DEGREES. ---------------------------------------------------------

Use this applet for the next task.

  1. Use the RED DOT to change the angle.
  2. Click "Take a Picture"
  3. Change the length of the fishing rod (without changing the angle).
What do you notice about the ratio for you new angle?

Calculate sin(___) for your new angle using a calculator:

Explore this applet:

Change the length of the fishing rod. What do you notice about the cos ratio ?

cos is called the COSINE ratio. Calculate cos(___) for your angle using a calculator:

Which ratio is COSINE (cos) ?

Select all that apply
  • A
  • B
  • C
  • D
Check my answer (3)

Change the length of the fishing rod.  What do you notice about the tan ratio ?

tan is called the TANGENT ratio. Calculate tan(___) for your angle using a calculator:

Which ratio is TANGENT (tan) ?

Select all that apply
  • A
  • B
  • C
  • D
Check my answer (3)

Summary:

Summary:
>> Write this down! <<

Assignment, Part 1: worksheet "Why Didn't Ms. Zorg..."

Strategy: 1) label the sides of the triangle (hypotenuse, adjacent, opposite) 2) write the ratio for the appropriate ratio (reduce the fraction if necessary) 3) solve the puzzle

Assignment, Part 2:

IXL Review - Trigonometric ratios in similar right triangles>> Earn 50 points Strategy: 0) locate the corresponding angle in the triangle with side measurements. 1) label the sides of the triangle (hypotenuse, adjacent, opposite) 2) write the ratio for the appropriate ratio (reduce the fraction if necessary)

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