1. I can find percent change and find the relative error in linear and nonlinear measurements.

2. Percent Change Expresses an amount of change as a percent of an original amount. If a new amount is greater, the change is a percent increase. If a new amount is less, it is a percent decrease. Ratio of the amount of change to the original amount

3. Finding a Percent Change

4. You Try! A store buys an electric guitar for $295 and marks up the price to $340. What is the markup expressed as a percent change? ≈15%

5. Relative Error Ratio of the absolute value of the difference of a measured (or estimated) value and an actual value compared to the actual value. When expressed as a percent, it is called percent error.

6. Practice A decorator estimates that a rectangular rug is 5 ft by 8 ft, but it is actually 4 ft by 8 ft. Find the percent error. 25%

7. Minimum and Maximum Dimensions Often, actual measurements are not known. You cannot always be completely accurate. Think about measuring with a ruler. Precision is limited and sometimes you have to round. The most any measurement can be off is by half of the unit used to measure.

8. Example You measure the length of a poster to be 18.5 in to the nearest half inch. What are the minimum and maximum possible lengths of the poster? You measured to the nearest half inch, so the greatest possible error is 0.25 in (half of your units) in either direction.

9. Greatest Possible Percent Error The dimensions of a gift box are shown to the nearest inch. What is the greatest possible percent error in calculating the box’s volume? What do we know? Greatest possible error is 0.5 in V = lwh What are we looking for? Solve

10. Continued

11. Assignment ODDS ONLY P.148 #7-23