[6E696365]

>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.

[danparsonson]

The "Sun-Pluto distance" is colloquially understood as both of those things - a distance in a straight line right now, and the radius of its orbit on average. I think it's far more common for people to assume the latter as I did, but feel free to ask around and find out for yourself. Note that the instantaneous Sun-Pluto distance varies considerably due to the eccentricity of its orbit, and the distance OP quoted is the orbital semi-major axis (what one might refer to as the orbital radius for the sake of brevity), not the present distance.

OP was mathematically correct, just a bit unclear. We really don't need to spend so much time on this.