[ben_w]

Looks like all three replies to this share the same misunderstanding of my intent, so I assume my use of “it’s” was unhelpfully vague.

1/pi is not rational and therefore not “a rational fraction”, but think 1/pi is “a fraction”.

[caddybox]

Your comment brought me to the realization that the relationship doesn't hold both ways. A rational number can always be written as a fraction but a fraction is not always rational. Never considered this before today :)