Here's my view:
The normal preposition, when talking about direct relationships, is
to:
proportional to
disproportionate to
in proportion to
However, in some cases,
with is okay.
a) The sculpture seemed out of proportion with/to its surroundings.
b) His ears were drawn out of proportion with/to his head.
I don't think these are great examples to show the difference, but I think they just about work to show what I mean.
In a), there's an idea of a mismatch, or a disharmony, which makes
with acceptable, even preferable to
to. The sentence is not
really about proportions. If you kept
with, you could replace the word
proportion with alternative words to keep the same basic sense of disharmony.
In b), there's a clearer sense of proportion, since we're talking more directly about size relationships. This isn't about someone's impression of disharmony as in sentence a) because the idea is that there is a very particular ear to head size relationship that should be achieved. For that reason,
with is much less acceptable, and
to is preferable.
I do accept that people are going to disagree with my analysis here.
