What Is the Cos of 90 Degrees?

The cosine values around the unit circle range from 1 to -1. Cosine has a value 1 at zero degrees and a value of -1 at 180 degrees. The other values assigned to cosine by the unit circle are 0.87 at 30 degrees, 0.71 at 45 degrees and 0.50 at 60 degrees. These values alternate between positive and negative depending on the quadrant in which they lie.