Trigonometric ratios of angles in radians

What You'll Learn

Evaluate trigonometric ratios (sine, cosine, tangent, secant) for angles in radians

Convert angles between radians and degrees to solve trigonometry problems

Identify reference angles and apply special triangle ratios in all four quadrants

Determine positive and negative signs using the CAST rule (Add Sugar To Coffee)

Find coterminal angles by adding or subtracting multiples of 2π

What You'll Practice

Evaluating sine, cosine, tangent, and secant for angles like π/3, 3π/4, and 7π/6

Converting radian measures to degrees and vice versa

Drawing angles in standard position and identifying terminal arms

Finding positive and negative coterminal angles in radian form

Applying special triangle ratios (30-60-90 and 45-45-90) in different quadrants

Why This Matters

Understanding trigonometric ratios in radians is essential for advanced math and physics. Radians are the standard unit in calculus, engineering, and scientific applications, making this skill crucial for your future STEM coursework and problem-solving in real-world contexts.

Before You Start — Make Sure You Can:

Combination of SohCahToa questions Find the exact value of trigonometric ratios ASTC rule in trigonometry (All Students Take Calculus)Converting between degrees and radians

This Unit Includes

9 Video lessons

Practice exercises

Learning resources

Skills

Radians

Trigonometric Ratios

Unit Circle

Reference Angles

CAST Rule

Coterminal Angles

Special Triangles

Angle Conversion

OH Curriculum Aligned