From your link..........
"Radius 1590s, "cross-shaft," from Latin radius "staff, stake, rod; spoke of a wheel; ray of light, beam of light"
"In the Theban Recession of the Book of the Dead, which is based upon Heliopolitan belief, we find Aten mentioned by the deceased thus :--- "Thou, O Ra, shinest from the horizon of heaven, and Aten is adored when he resteth {or setteth} upon this mountain to give life to the two lands. Hunefer says Ra, Hail Aten, thou the lord of beams of light, {when} thou shinest all faces {i.e., everybody} lives."
So RA "thou the lord of beams of light" & Radius
"ray of light, beam of light" is just a coincidence,
a chance?