Complementary angle relationship (sin x = cos(90-x))
Start lessonBegins with Exercise · Practice
Teacher tools for this standard
Lesson Plan · Guided Notes · Exit Ticket · Re-teach · Homework
Teacher tools for this standard
Lesson Plan · Guided Notes · Exit Ticket · Re-teach · Homework
- Lesson Plan →Objectives, pacing and practice, built from this lesson's brief.
- Guided Notes →One page your students fill in and keep.
- Exit Ticket →Three items at the end of class. No student accounts.
- Re-teach →After an exit ticket: who missed what, and what to do tomorrow.
- Homework →Assign practice; it grades itself.
"Solve problems using the relationship between sine and cosine of complementary angles."
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"Solve problems using the relationship between sine and cosine of complementary angles."
What you'll learn
- State the identities sin(x) = cos(90 - x) and cos(x) = sin(90 - x) for acute angles x
- Explain why these identities hold by analyzing the two acute angles in a right triangle
- Apply the relationship to determine unknown angles (e.g., if sin(x) = cos(35), find x)
- Use the relationship to simplify expressions or verify equivalences
- Solve SAT-style problems that test the complementary angle relationship directly
Slides
Step through the lesson, or watch it as a narrated video
Slides
In development
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Practice
Try it on your own
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