Ratios And Proportions
By: Eric Long
What are Rates, Ratios and Proportions?
*Rates are a comparison of two different units
*Ratios are a comparison of two things
*Proportions are 2 equal ratios that compares two things
Now you know!
The 2 Types Of Ratios
*Part to Part which is a part of the total number with another part of the total number
Ex: There are 25 students in the class, 12 are boys and 13 are girls
Or
*Part to Whole which is a part of the total number with the total number
Ex: In a classroom, 13 students are girls and there are 25 students in the classroom
Proportionality: To check if it's proportional or non-proportional
Proportional: Equal Ratios
Non-Proportional: Ratios are not equal
Solving Proportions:
2*3 6
----- = ----
4*3 12
Or
Cross Multiply
Look At The Picture Above
*These are not the only ways to solve, these are only the major ways to solve
How To Set Up Proportions
Number Word/Unit Number Word/Unit
---------------------------- = ----------------------------
Number Word/Unit Number Word/Unit
Ex: 3 Books 6 Books
------------- = -------------
6 Dollars 12 Dollars
*This is not the only kind of set up! This is only the regular set up and there are many more like the percent proportion, etc
The Types Of Proportions
2.Same 2 Words Twice: 3 Numbers Are Given(Some May Be Inferred); Regular Set Up
3.Constant Of Proportionality And Unit Rate: Amount For One Unit; Regular Set Up But With A Ratio Having A Unit Of One
4.Measurement And Scale Drawing: Changing Between 2 Different Units Or A Picture Of A Smaller Model/Drawing; Regular Set Up But With Different Measurement Units
5.Similar Figures: Same Shape, Different Size; Regular Set Up But Words May Be Long/Short, Length/Width, Etc
6.Percent: If There Is A Percent Or Percent Sign Use The Percent Proportion Which Is Part Over Whole, Percent Over 100