The lessons in this chapter involve a great deal of cross multiplying and then solving for the variable.
Basically, we setup the proportion then multiply the top number (numerator) of the first ratio by the bottom of the second. Then we multiply the bottom (denominator) of the first ratio by the top number of the second.
We can then divide to get the letter (variable) by itself.
A ratio is a comparison of two quantities using division.
A ratio can be written as a fraction, in word form, or with a colon.
It can compare a part of a group to the whole.
It can compare two parts of the same group.
It can compare the whole group to one of its parts.
A rate compares two things with different units of measure
Example of a rate:
2 liter bottle of soda for $2.99
53 meters every 10 minutes
A unit rate is different from a basic rate, because it makes a comparison to one unit of an item
60 miles per 1 hour
16 ounces per 1 pound
60 seconds per 1 minute
In order to convert a rate into a unit rate you need to divide.
6 miles in 2 minutes
6 divided by 2
Would give us 3 miles in 1 minute
3 miles per 1 minute is a unite rate
