Do we use ratios in the real world an d if not why are we learning this?

Ratios are hidden all over the real world. Whether you're measuring the speed of light, the rate of a chemical reaction, or the time it takes for a racecar to reach top speed, ratios are an integral part of quantifying real-life scenarios.

Can something that is infinite be a ratio?

Good question! Just to make it clear, value of infinity/infinity can be any number. The ratio can be 0, any finite value or infinity itself. On the other hand, we can say if we going to measure it quantitively, infinity at the numerator may not be equal to infinity at the denominator. So, we can not get any particular value from the ratio.

Can negative numbers be ratios?

Yes, ratios can be negative! For example, you could have _-3 / 4_ or _5 / -2_.

For the last problem would dividing 32.5 by 3 to get 10.83 then multiplying 10.83 by 6 and 12 be wrong? Because you don't get 65 you get 64.98 and 129.96.

I multiplied 32 and 1/2 by 2 because that gets me the answer of the 6 lollipops, and we are using fractions here not decimals :D

What is inverse proportion

Great question for sixth grade! Two nonzero quantities, x and y, are inversely proportional to each other if and only if their product xy is constant. This means that when x is multiplied by a nonzero factor, y is *divided* by that factor (for example, when x is doubled, y is halved). An example from real life involves speed, time, and distance. If the distance is held constant, then speed and time are inversely proportional to each other. For example, if you double your walking speed, then you would take half the amount of time to walk to school. Inverse proportionality relationships also occur in chemistry and physics. If the temperature of an ideal gas is held constant, then pressure and volume are inversely proportional to each other (Boyle’s Law). If the voltage of an electric circuit is held constant, then the circuit’s current and resistance are inversely proportional to each other (Ohm’s Law). Have a blessed, wonderful day!

how often will I see a ratio in the real world?

All the time, you drive in ratios (60 miles/hour), every recipe you follow is ratios, people often plan parties with ratios (2 deserts per person, or figuring out how much stuff you need to buy for the number of people you have). This does not even get into the practical uses of science, math, art, etc.

Main content

6th grade

Unit 1: Lesson 3

Equivalent ratios

Ratio tables

CCSS.Math:

6.RP.A.3

6.RP.A.3a

Google Classroom

Learn how to fill out tables of equivalent ratios.

A ratio table gives a bunch of equivalent ratios.

Let's look at an example where we'll build a ratio table.

Ben drinks start color #11accd, 1, end color #11accd glass of milk for every start color #e07d10, 2, end color #e07d10 cookies that he eats:

We can use this ratio to begin a ratio table:

Glasses of milk	Cookies
start color #11accd, 1, end color #11accd	start color #e07d10, 2, end color #e07d10

If Ben drinks start color #11accd, 2, end color #11accd glasses of milk, then he eats start color #e07d10, 4, end color #e07d10 cookies:

Let's use this to continue the ratio table:

Glasses of milk	Cookies
start color #11accd, 1, end color #11accd	start color #e07d10, 2, end color #e07d10
start color #11accd, 2, end color #11accd	start color #e07d10, 4, end color #e07d10

Notice that both of the ratios in the ratio table are equivalent:

If Ben drinks start color #11accd, 4, end color #11accd glasses of milk, then he eats start color #e07d10, 8, end color #e07d10 cookies:

Let's use this to continue the ratio table:

Glasses of milk	Cookies
start color #11accd, 1, end color #11accd	start color #e07d10, 2, end color #e07d10
start color #11accd, 2, end color #11accd	start color #e07d10, 4, end color #e07d10
start color #11accd, 4, end color #11accd	start color #e07d10, 8, end color #e07d10

Notice that all of the ratios in the ratio table are equivalent:

start fraction, start color #11accd, 1, end color #11accd, divided by, start color #e07d10, 2, end color #e07d10, end fraction, equals, start fraction, start color #11accd, 2, end color #11accd, divided by, start color #e07d10, 4, end color #e07d10, end fraction, equals, start fraction, start color #11accd, 4, end color #11accd, divided by, start color #e07d10, 8, end color #e07d10, end fraction

Let's practice!

Problem set 1:

Problem 1A

Current

Martha needs 28 strawberries for every 4 smoothies she makes.

Complete the table using equivalent ratios.

Strawberries	Smoothies
28	4
Your answer should be an integer, like 6 a simplified proper fraction, like 3, slash, 5 a simplified improper fraction, like 7, slash, 4 a mixed number, like 1, space, 3, slash, 4 an exact decimal, like 0, point, 75 a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text	3
70	Your answer should be an integer, like 6 a simplified proper fraction, like 3, slash, 5 a simplified improper fraction, like 7, slash, 4 a mixed number, like 1, space, 3, slash, 4 an exact decimal, like 0, point, 75 a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text

Sort by:

Want to join the conversation?

Faith Waters
Posted 5 years ago. Direct link to Faith Waters's post “Do we use ratios in the r...”
Do we use ratios in the real world an d if not why are we learning this?
Button navigates to signup pageComment on Faith Waters's post “Do we use ratios in the r...”
(166 votes)
Answer
- Danny
  Posted 5 years ago. Direct link to Danny's post “Ratios are hidden all ove...”
  Ratios are hidden all over the real world. Whether you're measuring the speed of light, the rate of a chemical reaction, or the time it takes for a racecar to reach top speed, ratios are an integral part of quantifying real-life scenarios.
  Comment on Danny's post “Ratios are hidden all ove...”
  (128 votes)
Mak Kochendorfer
Posted 6 years ago. Direct link to Mak Kochendorfer's post “Can something that is inf...”
Can something that is infinite be a ratio?
Button navigates to signup pageComment on Mak Kochendorfer's post “Can something that is inf...”
(54 votes)
Answer
- southside joji
  Posted 2 years ago. Direct link to southside joji's post “Good question! Just to ma...”
  Good question! Just to make it clear, value of infinity/infinity can be any number. The ratio can be 0, any finite value or infinity itself. On the other hand, we can say if we going to measure it quantitively, infinity at the numerator may not be equal to infinity at the denominator. So, we can not get any particular value from the ratio.
  Comment on southside joji's post “Good question! Just to ma...”
  (35 votes)
Peterson, Chase
Posted 3 years ago. Direct link to Peterson, Chase's post “Can negative numbers be r...”
Can negative numbers be ratios?
Button navigates to signup pageComment on Peterson, Chase's post “Can negative numbers be r...”
(35 votes)
Answer
- Evan
  Posted 3 years ago. Direct link to Evan's post “Yes, ratios can be negati...”
  Yes, ratios can be negative!
  For example, you could have -3 / 4 or 5 / -2.
  Comment on Evan's post “Yes, ratios can be negati...”
  (35 votes)
Rose Roberts
Posted 5 years ago. Direct link to Rose Roberts's post “For the last problem woul...”
For the last problem would dividing 32.5 by 3 to get 10.83 then multiplying 10.83 by 6 and 12 be wrong? Because you don't get 65 you get 64.98 and 129.96.
Button navigates to signup pageComment on Rose Roberts's post “For the last problem woul...”
(13 votes)
Answer
- tianao.wang
  Posted 3 years ago. Direct link to tianao.wang's post “I multiplied 32 and 1/2 b...”
  I multiplied 32 and 1/2 by 2 because that gets me the answer of the 6 lollipops, and we are using fractions here not decimals :D
  Comment on tianao.wang's post “I multiplied 32 and 1/2 b...”
  (14 votes)
Sudharshinis:)
Posted a year ago. Direct link to Sudharshinis:)'s post “What is inverse proportio...”
What is inverse proportion
Button navigates to signup pageComment on Sudharshinis:)'s post “What is inverse proportio...”
(12 votes)
Answer
- Ian Pulizzotto
  Posted a year ago. Direct link to Ian Pulizzotto's post “Great question for sixth ...”
  Great question for sixth grade!
  
  Two nonzero quantities, x and y, are inversely proportional to each other if and only if their product xy is constant. This means that when x is multiplied by a nonzero factor, y is divided by that factor (for example, when x is doubled, y is halved).
  
  An example from real life involves speed, time, and distance. If the distance is held constant, then speed and time are inversely proportional to each other. For example, if you double your walking speed, then you would take half the amount of time to walk to school.
  
  Inverse proportionality relationships also occur in chemistry and physics. If the temperature of an ideal gas is held constant, then pressure and volume are inversely proportional to each other (Boyle’s Law). If the voltage of an electric circuit is held constant, then the circuit’s current and resistance are inversely proportional to each other (Ohm’s Law).
  
  Have a blessed, wonderful day!
  Comment on Ian Pulizzotto's post “Great question for sixth ...”
  (19 votes)
MELCOLM
Posted 9 months ago. Direct link to MELCOLM's post “how often will I see a ra...”
how often will I see a ratio in the real world?
Button navigates to signup pageComment on MELCOLM's post “how often will I see a ra...”
(10 votes)
Answer
- David Severin
  Posted 9 months ago. Direct link to David Severin's post “All the time, you drive i...”
  All the time, you drive in ratios (60 miles/hour), every recipe you follow is ratios, people often plan parties with ratios (2 deserts per person, or figuring out how much stuff you need to buy for the number of people you have). This does not even get into the practical uses of science, math, art, etc.
  Comment on David Severin's post “All the time, you drive i...”
  (9 votes)
Kittylover16
Posted 3 years ago. Direct link to Kittylover16's post “the straberry and smoothe...”
the straberry and smoothes problem makes no sence.
Button navigates to signup pageComment on Kittylover16's post “the straberry and smoothe...”
(13 votes)
Answer
Vankerckhove, Will
Posted 3 years ago. Direct link to Vankerckhove, Will's post “This will not allow me to...”
This will not allow me to turn in my work its 9pm and it do tomorow. HELP.
Button navigates to signup pageComment on Vankerckhove, Will's post “This will not allow me to...”
(12 votes)
Answer
leland the genious
Posted 6 months ago. Direct link to leland the genious's post “i dont know da pizza one”
i dont know da pizza one
Button navigates to signup pageComment on leland the genious's post “i dont know da pizza one”
(9 votes)
Answer
- Caleb the disiple
  Posted 2 months ago. Direct link to Caleb the disiple's post “I was too but I think you...”
  I was too but I think you should work harder on ratios
  Button navigates to signup page
  (0 votes)
CarsonS
Posted 2 years ago. Direct link to CarsonS's post “what does ratios do with ...”
what does ratios do with real world what will we use them for in real world?
Button navigates to signup pageComment on CarsonS's post “what does ratios do with ...”
(8 votes)
Answer
- Indivara
  Posted 2 years ago. Direct link to Indivara's post “In a lot of things like m...”
  In a lot of things like measuring what and all ingredients you need to cook, and for example somebody just bolts out of the blue and asjs you a ratio question and u don't know ratio? What would u do? it would be better if you learn it on firsthand...
  Hope it helps
  Comment on Indivara's post “In a lot of things like m...”
  (0 votes)