A proportion is an equation that says that two or more ratios
are equal. For instance if one package of cookies contain 20
cookies that would mean that 2 packages contain 40 cookies
A proportion is read as "x is to y as a is to b".
The products xb and ay are called cross products. The cross
products of a proportion are always equal. If we want to check if
two ratios form a proportion we can just check their cross
Use cross product to determine if the two ratios form a
Here we can see that 2/16 and 5/40 are proportions since their
cross products are equal.
Percent means hundredths or per hundred and is written with the
symbol, %. Percent is a ratio were we compare numbers to 100 which
means that 1% is 1/100.
In a box of eight donuts two have pink sprinkles. Try to express
how many percent of the donuts in the box that have pink sprinkles
This proportion is called the percent proportion.
Fractions, percent and decimals can all represent the same
number, but they are expressed differently.
Decimal è percent: We can convert decimals into percent by
writing the decimal as a fraction with the denominator 1. We then
extend the fraction by 100 to get the decimal in percent.
Write 0.27 in percent.
Percent è decimal: write the percent as a fraction with the
denominator 100. A good thing to remember is that 100% = 1
Write 89% as a decimal.
Video lesson: Write in percent or as