Is there anyway to expand the information in a column and its relation in the
next column?

example, in column A, I have numbers 50, 52.1, 55, 58.8, 60, 65, 70, etc.
(up to 20,000)
in column B, I have a number I can divide them with to give me another
system of numbers. the divisor of 50 is 4.66, 52.1 is 4.88, 55 is 5.13, 58.8
is 5.46, 60 is 5.52, etc.

I'm building a form where I need to be able to have someone type in any
number (not just the ones in the table), and it can find the divisor and
divide to give them an answer.