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?
5 exercises available

Learn about the relationship between the sine of an angle and the cosine of its complementary angle, which is the angle that completes to 90°.

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

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