﻿ GreeneMath.com - Proportions Lesson

# In this Section:

In this section, we learn how to determine if two ratios or two rates represent a proportion. We start with determining if two fractions are equal in value. To do this, we utilize a procedure known as the “equality test for fractions”. This tells us that if two fractions are equal in value, their cross products must be equal. For example, one - fourth is equal to two - eighths. The cross products would be the same in each case: eight. Once we have mastered this concept, we apply the same logic to working with ratios and rates. To determine if two ratios or two rates represent a proportion, we simply check to see if their cross products are equal. We only think about the number parts, we do not look at the units. In the case of a rate, we must ensure that the same units are in the numerator and denominator of each.
Sections:

# In this Section:

In this section, we learn how to determine if two ratios or two rates represent a proportion. We start with determining if two fractions are equal in value. To do this, we utilize a procedure known as the “equality test for fractions”. This tells us that if two fractions are equal in value, their cross products must be equal. For example, one - fourth is equal to two - eighths. The cross products would be the same in each case: eight. Once we have mastered this concept, we apply the same logic to working with ratios and rates. To determine if two ratios or two rates represent a proportion, we simply check to see if their cross products are equal. We only think about the number parts, we do not look at the units. In the case of a rate, we must ensure that the same units are in the numerator and denominator of each.