There are infinitely many ways to answer this. The easiest of which is this ratio
2 cups dressing: 4 heads cabbage
we simply write the two values side by side placing a colon between the two numbers.
If you divide both parts of that ratio by 2 (the GCF), then
2/2 = 1
4/2 = 2
So the new reduced ratio is now
1 cup dressing: 2 heads cabbage
To get any equivalent ratio, multiply or divide both sides by the same number. You can use any number you want to multiply or divide just as long as both sides are handled the same to keep things balanced. Think of it as an equation. This is why there are infinitely many possible answers. Two of which I have placed in bold above.