A proportional relationship is a relationship between two variables where their ratios are equivalent. In other words, one variable is always a constant value times or divided by the other variable, and that constant is known as the "constant of proportionality". The key features of a proportional relationship are:
- The ratio between the two variables is always the same.
- The graph of the proportional relationship equation is a straight line through the origin.
- The constant of proportionality is the same for all values of the variables.
To determine if two quantities have a proportional relationship, we can check if their ratios are equivalent. If the ratios are equivalent, then the two quantities vary directly with each other, and we say that one variable varies directly as the other. If the ratios are not equivalent, then the relationship is not proportional.
