Trigonometry
Unit Circle
Radians, degrees, and the unit circle
Learning Objectives
Discussion Starters
Differentiation Ideas
Presentation Mode
lessons (2)
Introduction to the Unit Circle
Learn what the unit circle is and how it connects angles to trigonometric values.
Advanced25 minTeacher View
Radians and Degrees
Learn to convert between radians and degrees, two ways of measuring angles.
Advanced25 minTeacher View
The unit circle is a circle with radius 1 centered at the origin. It provides a geometric foundation for understanding trigonometric functions for all angles, not just those in right triangles.
What Students Will Learn
- Understand the unit circle definition
- Find coordinates on the unit circle
- Evaluate trig functions using the unit circle
- Memorize key angle values
- Connect to the coordinate plane
Frequently Asked Questions
What is the unit circle?
A circle with radius 1 centered at (0,0). Any point on it has coordinates (cos θ, sin θ) where θ is the angle from the positive x-axis.
Why is the unit circle important?
It defines sine and cosine for ALL angles (not just 0-90°), shows periodicity, and connects trig to coordinates.
What values should I memorize?
Key angles: 0°, 30°, 45°, 60°, 90° and their equivalents in radians (0, π/6, π/4, π/3, π/2).