If you are to find the ratio you divide. So you are looking for

Now you need to know how many sig digs you need for your final answer. When multiplying or dividing your answer has the number of sig digs that is the least of the number of sig digs of any of the numbers involved. For example

will have two digits because 0.20 has two digits and 4.33 has three.

So how many digits does 0.14635 have? How many does 400 have?

-Dan