Trigonometry with right triangles

Learn the basics of trigonometry: What are sine, cosine, and tangent? How can we use them to solve for unknown sides and angles in right triangles?

Trigonometric ratios of special triangles

Learn to find the sine, cosine, and tangent of 45-45-90 triangles and also 30-60-90 triangles.

Introduction to the Pythagorean trigonometric identity

Learn about a very special trigonometric identity that follows from the Pythagorean theorem.