>It's clearer to compare a radius to a radius, is all.
The OP wasn't comparing a diameter to a radius, he was comparing one line to another line: the diameter of the outer ring (line going from one end to the other passing through the middle) and the distance between Pluto and the Sun (line between two points). The fact that Pluto orbits the Sun is just a coincidence for the purposes of this comparison.
The OP wasn't comparing a diameter to a radius, he was comparing one line to another line: the diameter of the outer ring (line going from one end to the other passing through the middle) and the distance between Pluto and the Sun (line between two points). The fact that Pluto orbits the Sun is just a coincidence for the purposes of this comparison.