Patterns in the 30-60-90 Table

Sine and cosine ratios have more in common than just their names—they are complementary to each other. Using a 30-60-90 triangle, pupils create a table of the sine and cosine of the acute angles. The learners describe the relationships between pairs of trigonometric ratios of complementary angles and develop a reason for the occurrence.

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CCSS: Designed
Instructional Ideas

  • Provide other sets of complementary angles for class members to see if the pattern still holds
Classroom Considerations

  • Individuals should know the definition of the sine and cosine ratios
  • Class members should not use a calculator to better see the relationship
Pros

  • Contains work examples to illustrate misconceptions
  • Provides instructional suggestions
Cons

  • None
Common Core