Unit Circle Citadel

Levels 34–99 · unitCircle

A citadel built on a perfect circle of radius 1. Read sin and cos at standard angles to claim the battlements.

Study Before You Play

Brush up on these topics to sharpen your skills for this zone.

Introduction to Trigonometry

The unit circle defines sin and cos for all angles, not just right triangles.

The Unit Circle

sin(θ) is the y-coordinate and cos(θ) is the x-coordinate of the point at angle θ.

Angles & Triangles

Standard angles 0°, 30°, 45°, 60°, 90° come from special right triangles.