Which trigonometric function equals the ratio of the opposite side to the adjacent side in a right triangle?

In a right triangle, the tangent function is defined as the ratio of the length of the opposite side to the length of the adjacent side. This relationship is fundamental in trigonometry, particularly for calculating angles and side lengths in right triangles.

To clarify further, the sine function represents the ratio of the opposite side to the hypotenuse, while the cosine function represents the ratio of the adjacent side to the hypotenuse. The secant function is the reciprocal of the cosine function, which also does not relate directly to the sides of the triangle in the same way as tangent does.

Thus, when determining the ratio that specifically involves the opposite side and the adjacent side, tangent is the correct function to use. Understanding this relationship is crucial for solving problems that involve right triangles and trigonometric functions.