<img src="https://d5nxst8fruw4z.cloudfront.net/atrk.gif?account=iA1Pi1a8Dy00ym" style="display:none" height="1" width="1" alt="" />
Dismiss
Skip Navigation

Ratios in Simplest Form

Simplify ratios using greatest common factors.

Atoms Practice
Estimated20 minsto complete
%
Progress
Practice Ratios in Simplest Form
Practice
Progress
Estimated20 minsto complete
%
Practice Now
Ratios in Simplest Form

Let’s Think About It

License: CC BY-NC 3.0

Grace is working on an assignment. She has to survey 50 people and ask if they are either right-handed or left-handed. Out of the 50 people she surveyed, 5 were left-handed and 45 were right-handed. How can Grace use this information to describe the results of her survey?

In this concept, you will learn how to simplify ratios and then compare and draw conclusions.

Guidance

A ratio is the comparison of two quantities. Ratios can involve large quantities that may not represent a clear comparison. Simplify ratios to make them easier to evaluate. Since ratios can also be written as fractions, you can simplify ratios the same way you simplify fractions.

Let’s look at the ratio of left-handed people to right-handed people. The ratio of left-handed people to right handed people is 5 to 45. First, write the ratio using the fraction notation.

\begin{align*}\frac{5}{45}\end{align*}

Then, find the greatest common factor (GCF) to find the simplest form of the ratio. The GCF is the largest factor share by both numbers. The GCF of 5 and 45 is 5.

Next, divide the numerator and the denominator by the GCF.

\begin{align*}\frac{5 \div 5}{45 \div 5}=\frac{1}{9}\end{align*}

The simplest form of the ratio \begin{align*}\frac{5}{45}\end{align*} is \begin{align*}\frac{1}{9}\end{align*}, which can also be written as 1 to 9 or 1 : 9.

There is one left-handed person for every nine right-handed people.

Remember, when you simplify a ratio, the value of the ratio does not change. Therefore, a ratio and its simplest form are equivalent ratios.

\begin{align*}\frac{5}{45}=\frac{1}{9}\end{align*}

Guided Practice

Find the simplest form for the following ratio.

\begin{align*}\frac{12}{18}\end{align*}

First, find the GCF of 12 and 18. The GCF is 6.

Next, divide the numerator and the denominator by 6.

\begin{align*}\frac{12 \div 6}{18 \div 6}=\frac{2}{3}\end{align*}

The simplest form of \begin{align*}\frac{12}{18}\end{align*} is \begin{align*}\frac{2}{3}\end{align*}.

Examples

Simplify the following ratios. Write the simplified ratio as a fraction.

Example 1

\begin{align*}\frac{2}{10}\end{align*}

First, find the GCF of 2 and 10. The GCF is 2.

Next, divide the numerator and denominator by 2.

\begin{align*}\frac{2 \div 2}{10 \div 2}=\frac{1}{5}\end{align*} 

The simplest form of \begin{align*}\frac{2}{10}\end{align*} is \begin{align*}\frac{1}{5}\end{align*}.

Example 2

\begin{align*}6 \text{ to } 8\end{align*}

First, find the GCF of 6 and 8. The GCF is 2.

Next, divide the both numbers by 2.

\begin{align*}\begin{array}{rcl} 6 \div 2 & = & 3\\ 8 \div 2 & = & 4 \end{array}\end{align*}

Then, write 3 to 4 as a fraction.

\begin{align*}\frac{3}{4}\end{align*}

The simplest form of 6 to 8 is 3 to 4 or \begin{align*}\frac{3}{4}\end{align*}.

Example 3

\begin{align*}5: 20\end{align*}

First, find the GCF for 5 and 20. The GCF is 5.

Next, divide both numbers by 5.

\begin{align*}\begin{array}{rcl} 5 \div 5 & = & 1\\ 20 \div 5 & = & 4 \end{array}\end{align*}

Then, write 1 : 4 as a fraction.

\begin{align*}\frac{1}{4}\end{align*}

The simplest form of 5 : 20 is 1 : 4 or \begin{align*}\frac{1}{4}\end{align*}.

Follow Up

License: CC BY-NC 3.0

Remember Grace’s survey?

Of the 50 people she surveyed, 5 were left-handed and 45 were right-handed. Use a different ratio. Simplify the ratio and draw a conclusion.

First, decide which ratio to use and write it as a fraction. Let’s use the ratio of left-handed people to the total number of people surveyed.

\begin{align*}\frac{5}{50}\end{align*}

Next, find the GCF. The GCF of 5 and 50 is 5.

Then, divide the numerator and the denominator by 5.

\begin{align*}\frac{5 \div 5}{50 \div 5}=\frac{1}{10}\end{align*}

The simplest form of \begin{align*}\frac{5}{50}\end{align*} is \begin{align*}\frac{1}{10}\end{align*}.

There is one left-handed person for every ten people surveyed.

Video Review

https://www.youtube.com/watch?v=JWmCiZwoyMs

https://www.youtube.com/watch?v=-YLWlPVEpbQ

Explore More

Find the simplest form for each ratio. Write your answer as a fraction.

  1. 2 to 4
  2. 3 : 6
  3. 5 to 15
  4. 2 to 30
  5. 10 to 15
  6. \begin{align*}\frac{4}{6}\end{align*}
  7. 3 : 9
  8. 6 : 8
  9. \begin{align*}\frac{2}{8}\end{align*}
  10. \begin{align*}\frac{4}{16}\end{align*}
  11. 10 to 12
  12. 7 : 21
  13. 12 : 24
  14. 25 to 75
  15. \begin{align*}\frac{27}{30}\end{align*}
  16. \begin{align*}\frac{48}{60}\end{align*}
  17. \begin{align*}\frac{18}{80}\end{align*}

Answers for Explore More Problems

To view the Explore More answers, open this PDF file and look for section 8.2. 

Vocabulary

Equivalent

Equivalent

Equivalent means equal in value or meaning.
Greatest Common Factor

Greatest Common Factor

The greatest common factor of two numbers is the greatest number that both of the original numbers can be divided by evenly.

Image Attributions

  1. [1]^ License: CC BY-NC 3.0
  2. [2]^ License: CC BY-NC 3.0

Explore More

Sign in to explore more, including practice questions and solutions for Ratios in Simplest Form.

Reviews

Please wait...
Please wait...

Original text