A ratio is a way to compare two quantities, showing how much of one thing there is compared to another. The ratio 3:4 means that for every 3 units of one quantity, there are 4 units of another. This can be applied in various contexts, such as mixing ingredients in a recipe or comparing the number of boys to girls in a classroom. In the 3:4 ratio, the first number (3) represents one part, while the second number (4) represents another part. This ratio can also be expressed as a fraction, 3/4, which indicates that the first quantity is three-quarters of the second. Ratios help in understanding relationships between different quantities clearly.