What term refers to the relationship between one part and another part, often expressed as a statement of equality between two ratios?

The term that refers to the relationship between one part and another part, often expressed as a statement of equality between two ratios, is the concept of proportion. A proportion states that two ratios are equal, which is mathematically represented as ( \frac{a}{b} = \frac{c}{d} ). This means that the relationship between the numbers in one ratio is consistent with the relationship between the numbers in the other ratio.

Understanding proportions is crucial in various fields, including health science, where they are often used to analyze data, calculate dosages, and compare quantities. This concept is distinct from a ratio, which simply compares two quantities without the necessity of establishing equality. A percentage is a specific way to express a ratio in terms of a part per hundred. Comparison is a broader term that does not specifically denote equality of ratios and can refer to a variety of different relationships between quantities. Proportion specifically underscores the equality aspect, making it the correct choice.