The percent equation is often used to solve problems. It goes like this:
Rate is the ratio that the percent represents (
Total is often called the base unit.
Part is the amount we are comparing with the base unit.
Finding a Percent of a Total
Find 25% of $80.
We are looking for the part. The total is $80. ‘of’ means multiply.
Expression Values and Percentages
Express $90 as a percentage of $160.
This time we are looking for the rate. We are given the part ($90) and the total ($160). Using the rate equation, we get
Finding the Total Sum
$50 is 15% of what total sum?
This time we are looking for the total. We are given the part ($50) and the rate (15%, or 0.15). Using the rate equation, we get
$96 is 12% of what total sum?
This time we are looking for the total. We are given the part ($96) and the rate (12%, or 0.12). Using the rate equation, we get
Find the following.
- 30% of 90
- 27% of 19
- 16.7% of 199
- 11.5% of 10.01
- 0.003% of 1,217.46
- 250% of 67
- 34.5% of y
- 17.02% of y
- x% of 280
- a% of 0.332
To view the Review answers, open this PDF file and look for section 3.14.
Texas Instruments Resources
In the CK-12 Texas Instruments Algebra I FlexBook® resource, there are graphing calculator activities designed to supplement the objectives for some of the lessons in this chapter. See http://www.ck12.org/flexr/chapter/9613.