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Learning Goal

Part of: Extend the domain of trigonometric functions using the unit circle — 1 of 4 cluster items

Understand radian measure

HSF.TF.A.1

**HSF.TF.A.1**: Understand radian measure of an angle as the length of the arc on the unit circle subtended by the angle.

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HSF.TF.A.1: Understand radian measure of an angle as the length of the arc on the unit circle subtended by the angle.

What you'll learn

  1. Define a radian as the measure of an angle whose arc length on the unit circle equals the radius
  2. Explain why a full rotation equals 2pi radians by relating circumference to radius
  3. Convert between degree and radian measures using the relationship 180 degrees = pi radians
  4. Identify radian measures of key angles: pi/6, pi/4, pi/3, pi/2, pi, and 2pi
  5. Justify why radians are a natural unit of angle measure for mathematics
  6. Label angles in standard position on the unit circle using radian measure

Slides

Interactive presentations perfect for visual learners • Interactive presentation

Slide Video

Watch narrated slides play like a video lesson • Narrated slide playback

Exercises

Practice problems to build fluency and understanding • 1 exercises