2 to 4 and 12 to 20 are these equivalent

No, i would look at these side by side.

A ratio is like a fraction so

2/4 and 12/20

Let's try simplifying 12/20.

Divide each side by 4 and that is 3/5.

This definitely does not equal 2/4

- now let's try this from the 2/4 perspective:

2/4

LCD would be 20. Multiply top and bottom by 5. It would equal 10/20 and not 12/20.

So either way it is not equivalent

They are not equivalent, you can cross multiply