In the triangle shown, and
The cosine ratio is the same regardless of the size of the right triangle. So, it is often easiest to consider a right triangle with a hypotenuse of length .
The cosine ratio can also be thought of as a function, which takes different values depending on the measure of the angle. You can measure an angle in degrees or radians .
The reciprocal of the cosine ratio is known as secant ratio of an angle, abbreviated as "sec".
In the above example, and .