In order to understand the coordinate values of each angle, we must go back to our Special Right Triangles (SRTs).
Please watch the following video as I demonstrate how the SRTs determine the coordinate values in the first Quadrant of the Unit Circle:
Now that we have all the components of the Unit Circle in place, with their origins demystified, we can move on to how the symmetry of the Unit Circle is the key to its easy memorization in the Finished Circle.