What does cosθ equal in terms of the sides of a right triangle?

In a right triangle, the cosine of an angle θ is defined as the ratio of the length of the adjacent side to the length of the hypotenuse. This is an important concept in trigonometry, as it helps to relate the angles of a triangle to the lengths of its sides.

To clarify, the adjacent side is the side that is directly next to the angle θ, and the hypotenuse is the longest side of the triangle, which is always opposite the right angle. Thus, using the definition of cosine, we can express it mathematically as:

[ \cos(θ) = \frac{\text{Adjacent side}}{\text{Hypotenuse}} ]

This ratio can be applied in various contexts, such as solving for unknown sides in a right triangle or determining angles when certain side lengths are known. It is foundational to many concepts in both geometry and higher-level mathematics.