Concepts

Proportion is a statement that two ratios are equal. It can be written in two ways: as two equal fractions ab = cd or using a colon, a:b = c:d.

Proportional - when two quantities have a constant ratio or unit rate. 
Non-proportional - when two quantities don’t have a  constant ratio or unit rate.
Equivalent ratios have the same value

Rules

To find an equivalent ratio, multiply or divide both numbers in a ratio by the same value.

Example

Select the ratio that is equivalent to the given ratio.

15 books$3

Solution

1.Multiply or divide the numerator and the denominator by the same number to get its equivalent ratio.

Check case A: 1 book, 15 ÷ 15 = 1
Divide the given fraction by the conversion factor:   15 ÷ 13 ÷ 1 ≠ 15

Check case B: 5 books, 15 ÷ 3 = 5
Divide the given fraction by the conversion factor:   
15 ÷ 53 ÷ 5 ≠ 515

Check case C: 30 books, 15 × 2 = 30
Divide the given fraction by the conversion factor:   
15 × 23 × 2 ≠ 306

Answer: 30 books per $6

Pre-requisite Skills

Understand Ratios (6.6.1)

Ratios and Fractions (6.6.2)

Identify and Write Equivalent Ratio (6.6.3)

Finding Equivalent Ratios Using Tables (6.6.4)

Ratio Applications (6.6.11)

Unit Rate Applications (6.6.12)

Proportional Relationships Applications (6.6.13)