Can 4:3 be a ratio?

Yes, 4:3 is a ratio. A ratio is a way of comparing two or more quantities. It is expressed using a colon (:) or a slash (/) to separate the numbers. In this case, 4:3 represents the ratio of two numbers, with 4 being the first number and 3 being the second number. This ratio can represent various things, such as the aspect ratio of a screen, the dimensions of a rectangle, or the proportion of two quantities.