Maybe I missed it somewhere in this meandering thread, but has anyone
considered the "bowl" might be slightly tapered inwards at the top? I
didn't see any statements to the contrary. And nothing said the OD
and circumference were measured at the same point on the surface of
the bowl.

It would be trivial to make a tapered bowl shape with a 10 inch max OD
and 30 inch circumference "at the top"! Maybe a hint was given early
on when he said it resembled a dog dish? Many dog dishes have this
shape, as it makes the dish more stable. If this is the answer, then
the ratio of 3-1 was a red herring all along to drag in the "pi=3"
crowd. :-)

If it's not tapered in at the top, then it is impossible. A circle is
the smallest perimeter enclosing any given space. (in Euclidian space,
anyway). Any variation in rim shape can only make it longer, not
shorter. And anyway, he already said it was "round". And one thing
we can be sure of, I think, is that pi is 3!

Bob