Python: uses underscores. Java, Javascript: camelcase. .NET: Capitalize. And so forth, those are the conventions that professionals use, so stick to them for an interview.

`biggestSize = 99999999 #MaxInt` This is returned if the caller passes you 0 for slicesToFind, so you're returning a nonsense value in that case. Either raise an exception (preferred as it catches errors fast) or return None.

`def area(size)` You're using pi r^2, so size is a radius, but it seems you call it with a diameter. This is why choosing distinct names is very important.

`newSize = (originalSize / newSlicesInCake)` Again, using "size" all over the place is confusing. I'd write something like `new_slice_area = (original_cake_area / new_slice_count)`.