The cosine of 1 is 0.99 when evaluated in degrees and 0.54 when evaluated in radians. The value can be found by using the cosine function on a calculator or by evaluating the function manually.
The cosine of an angle is evaluated by forming a right triangle and finding the ratio of the length of the side adjacent to the angle over the length of the hypotenuse. The hypotenuse is the longest side of a right triangle and is opposite the 90 degree angle. An angle can be expressed either in degrees or in radians, which is based on the segment of a circle represented by the angle.