Aside from your recommendation letters, do you think your application is stronger for Georgetown College than for McDonough?
The acceptance rate for the College is at or below that for McDonough, so applying to the College won’t be significantly easier in general. If you are otherwise applying to business programs and have interests, awards, and extracurriculars that support business, how difficult will it be to re-work them to present a top notch non-business application?
Similarly, can you write a better essay to answer the Georgetown College prompt or the McDonough prompt?
If you present a much more compelling case for being a business student, then consider approaching a math teacher with a strong, written case for your interest and performance in math: topics you have enjoyed, class discussions that were especially interesting, and any other ways that you could convey yourself as a math student that could help them with a LOR.
Not all applications hinge on an amazing LOR. Carefully weigh whether you would have a robust business app with a lukewarm LOR vs a less stellar arts & sciences app and a stronger LOR.