what's the correct usage?

[keya mukherji]

if I want to talk about a ration between two things or two numbers, what preposition should I be using? I mean should it be like this - the ratio between 2 and 4. Or should it be - ratio of 2 and 4. and if both these prepositions are applicable then where exactly can they be used? please explain.

[Rover_KE]

We usually say '...in the ratio of two to four', which we write as '...in the ratio 2:4'.

Rover