# Ratios and Proportions (Geometry)

In this lesson I will teach you about ratios and proportions.  Because you did great in algebra you should already be a master at ratios and proportions- but if you’re a little unsure don’t worry I will review the topic completely.  Let’s remember that ratios and rates are just fractions.  What makes them unique is that ratios and rates are fractions that use numbers with units of measure.  Example 1/3 is a fraction however 1 teacher / 3 students is a ratio.  Now a proportion is an equation of two equal ratios or rates- i.e. an equation of two equal fractions.  The primary way we solve a proportion is by using something called the “cross-product”.  As you might already know you need to have great algebra skills to do well with ratios and proportions.  I will be reviewing a good amount of the algebra skills you need in the lesson but if you need more help please go back and review ratios and proportions in your algebra notes.  One thing that will be new to most students in this lesson is the property of ratios- this is usually not taught in algebra 1 but you need to know it.  I can’t stress how important it is for you to be able to solve ratio and proportion problems as this will be the primary skill you will need for many more lessons.  Good luck!