Proportions can be used to solve word problems. The steps are to set up the proportion using the ratios given, cross multiply the terms, and then solve the proportion to find the unknown value. For example, a proportion problem could involve rooms and minutes, setting up 5 rooms to 15 minutes as the ratio, cross multiplying 15x=300, then solving to get x=20 minutes. Percent problems follow the same steps, setting up the ratio as a percentage, cross multiplying terms, and then solving the proportion. While setting up proportions was easy, some students found cross multiplying and determining the correct numbers to use as the hardest parts. However, solving the proportion was generally the easiest part of the process.

1. ProportionsProportions
by Andre Goinsby Andre Goins

2. Example proportions word problem
Step 1:Set up the
proportion.
x
15*x=5*60
15x=300
X=20
/15/15
Rooms
Minutes
5
15 60
Step 2: cross
multiply (multiply
the diagonals
Step 3:solve the
proportion

3. Example percents problem
Step 1:fill in the
“is/of”
x
100*x=49*300
100x=14700
X=147
/100/100
49
100 300
Step 2: cross
multiply
Step 3:

4. Unit Reflection
• I liked… Setting the proportions up.
• I didn’t like…cross multiplying
• The hardest part was…figuring out what
number to use.
• The easiest part was…solving the
proportion.