How do you write 5 is to 1 as 20 is to 4 as a proportion in fractional notation???

To write "5 is to 1 as 20 is to 4" as a proportion in fractional notation, you would set up the ratio like this:

5/1 = 20/4

This can also be simplified to:

5/1 = 5/1

Therefore, the proportion in fractional notation is 5/1 = 20/4.