Mathematics ACT Aspire Practice Test 2026 – Complete Study Resource

Proportional relationships are defined by having a constant ratio between two quantities. This means that as one quantity changes, the other quantity changes at a consistent rate, which can be expressed mathematically as \( y = kx \), where \( k \) is the constant of proportionality.

In such relationships, if you were to create a table of values for the two quantities, the ratios of the corresponding values would always yield the same number. For example, if the quantities are \( x \) and \( y \), and the pair is (2, 4), (3, 6), and (4, 8), the ratios \( 4/2 \), \( 6/3 \), and \( 8/4 \) all equal 2, demonstrating that the relationship is proportional.

This concept is foundational in understanding ratios and can be applied in various contexts, such as in direct variation problems. It distinguishes proportional relationships from other types of relationships, where ratios may change and do not maintain a constant value.