What does cosine (cos) represent in a right triangle?

Cosine (cos) in the context of a right triangle specifically represents the ratio of the length of the adjacent side to the length of the hypotenuse. In a right triangle, if you consider one of the non-right angles, the adjacent side is the side that forms that angle along with the hypotenuse. The hypotenuse is always the longest side of the triangle, opposite the right angle.

This relationship is fundamental in trigonometry and allows for the calculation of angles and side lengths in right triangles. Understanding this ratio is crucial for solving problems related to angles, distances, and various applications of geometry in fields such as physics and engineering.