In a major key/scale, the major chords are the root, the fourth and the fifth. If you look at the root chord on the circle, the 4th is one step counter-clockwise from the root and the 5th is one step clockwise from the root.
Ahhh, ok. That answers another question I had. 1 step CCW and 1 step CW from the root gives us the common 1-4-5 used in so many songs?