Cambridge IGCSE Mathematics · Syllabus 0580 · Number
Ratio and Proportion
What is Ratio and Proportion?
A ratio compares two or more quantities of the same kind measured in the same unit, written with colons and simplified by dividing every part by a common factor. Proportion is the relationship between those quantities when one changes: in direct proportion their quotient stays constant, and in inverse proportion their product stays constant.
This definition is part of the Number chapter in Cambridge IGCSE Mathematics.