Conditional Formatting based on a ratio

I have a cell returning a ratio based on the values in 2 other cells. The calculation is a fraction, and the formatting is a custom formatting of 0.0":1"

My goal is a ratio of 4:1. I want the "actuals" cell to be red if it is showing 4.1:1 or more....and green if it is 4:1 or less. I know how to create conditional formatting, but because it's a ratio, I can't seem to get the right formula in my conditional formatting that will return the right colour.

Any ideas? See attached for a very simple example.

The fact that it's a ratio doesn't matter; it's just a number. Conditional format in the usual way.