Ratios and Proportions

This section has the following videos:

  • Lesson Video
  • Example Set A Practice Problems (Video Solutions)
  • Example Set B Practice Problems (Video Solutions)
  • Example Set C Practice Problems (Video Solutions)
  • Example Set D Practice Problems (Video Solutions)

Rates, ratios and proportions go together like a cheeseburger, fries and a coke.  So what’s this bond I speak of with these terms?  First let me start by saying rates and ratios are nothing more than fancy fractions (I’ll explain in a second).  Next a proportion is nothing more that an equation involving two equal fractions like 1 / 2 = 3 /6.    Ok back to rates and ratios. Like I said they are nothing more than fractions but fractions that compare numbers that are counting something (example 20 cars, 10 bats, 3 trees). Ratios are fractions where the numerator and denominator have numbers that measure the same thing like 10 cats / 30 cats.  Rates have different units of measure like 60 miles / 2 hours. Now that you know what a rate and ratio are we can move onto proportions.  Like I said proportions are equations that involve two equal fractions often these fractions are rates and ratios- see the connection now with rates, ratios and proportions?  Let me stress one huge point here:

when you have a proportion you can solve it using the cross-product ( see below); your ability to identify an equation as a proportion and solve it using the cross-product is key to overall success in algebra…learn it well my friend!