A proportional relationship in math is a relationship between two variables where their ratios are equivalent. In other words, one variable is always a constant value times the other, and that constant is known as the "constant of proportionality". For example, if we have a proportional relationship between the number of eggs and cups of milk, the ratio between the number of eggs and cups of milk will stay the same throughout the table.

To determine if two variables have a proportional relationship, we can examine the ratio between them. If the ratio between the two variables is always the same, then they have a proportional relationship. On the other hand, if the ratio between the two variables is not always the same, then they do not have a proportional relationship.

Proportional relationships are important in many areas of math, including algebra, geometry, and statistics. They are used to solve problems involving ratios, rates, and percentages, and they are also used to create graphs and tables that show how two variables are related.