Trigonometry involves studying the relationships between the angles and sides of triangles, particularly right triangles. To perform trigonometric calculations, you typically use sine, cosine, and tangent functions, which relate an angle to the ratios of the lengths of the sides. For example, in a right triangle, the sine of an angle is the ratio of the opposite side to the hypotenuse, the cosine is the adjacent side to the hypotenuse, and the tangent is the opposite side to the adjacent side. You can use these functions along with the Pythagorean theorem to solve problems involving angles and side lengths.