Unit Circle Basics for the SAT

SAT Math · Axiom Academy

Understand the unit circle, radian measure, and key trigonometric values that appear on the SAT. In this lesson, you'll master: What the unit circle is and why it matters Radians vs. degrees and how to convert between them Key angles on the unit circle (0°, 30°, 45°, 60°, 90°, etc.) How to find sin and cos values for standard angles Properties of the unit circle that make calculations easier The unit circle is a circle with radius 1 centered at the origin (0, 0) on a coordinate plane. For any point (x, y) on the unit circle at angle from the positive x-axis: Angles can be measured in two ways: degrees and radians. The SAT uses both, so you need to know how to convert. Key Angles and Trigonometric Values The SAT frequently uses these standard angles. You should know the sin and cos values for all of them: Without a calculator, find and using the unit circle. At 60°, the point on the unit circle is (the x-coordinate) (the y-coordinate) Question 1: Degree to Radian Conversion Question 3: Using the Pythagorean Identity Unit Circle: Radius 1, equation x^2 + y^2 = 1 Coordinates: For angle , the point is Radians: radians; convert using Key Angles: Know sin and cos for 0°, 30°, 45°, 60°, 90°

This is the written version of the interactive lesson above. See the full SAT Math course.