Unit Circle
Radians, degrees, and the unit circle
Learning Objectives
Discussion Starters
Differentiation Ideas
Presentation Mode
lessons (2)
1
Introduction to the Unit Circle
Learn what the unit circle is and how it connects angles to trigonometric values.
Advanced25 minTeacher View
2
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).