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Definition1

Title: Measurement

Grade Lesson s3-p2

Explanation: The best way to understand PSAT-4 is by looking at some definitions. Take turns and read each definition for easy understanding.

Definition

Topics → Definition Example1 Example2

Definition: Ratios

A ratio is a quantitative relationship between two numbers showing how many times one value contains or is contained within the other.

It is expressed as "a to b" or \$a/b\$, where a and b are the two quantities being compared.

$1$

Explanation:

The ratio 500,000:200,000 simplifies to 5:2 when both numbers are divided by their greatest common divisor, which is 100,000.

Definition: Proportion

A proportion is an equation that states that two ratios are equal.

It is a way to express that two sets of quantities have the same relative size or that one quantity is a multiple of the other.

Proportions are written in the form \$a/b = c/d or a:b=c:d\$, where a, b, c, and d are numbers, and b and d are not zero.

$2$

Explanation:

To find the third proportional number to 9 and 12, assign it the variable x. Use the proportion 9 : 12::12 : x.

Cross-multiply to get x = 16. Therefore, the third proportional number is 16.