Proportionality refers to situations where two quantities change at a constant rate relative to each other. Proportional relationships occur in many areas of mathematics like geometry, measurement, rates, and scale drawings. Examples include directly proportional relationships like the relationship between distance and time for a constant speed. Non-examples are situations where the quantities do not change at a constant rate, like area of a circle relative to its radius. Students may struggle with setting up and solving proportions, identifying proportional relationships, and determining if a situation demonstrates proportional thinking.

1. Definition/Characteristics: Contexts/mathematical topics in which
proportionality occurs:
P
PROPORTIONALITY
Examples of proportional situations: Non-examples of proportional situations:
Difficulties that students might encounter as they solve proportionality problems:
A derivative OGAP product created for MMSTLC October 2008. Original materials were developed as a part of The Vermont
Mathematics Partnership funded by a grant provided by the US Department of Education (Award Number S366A020002) and the
National Science Foundation (Award Number EHR-0227057)