Ch. 2 Vocabulary 7.) Ratio 8.) Rate 9.) Unit rate 10.) Conversion factor 11.) Unit analysis

2-6 Ratios, Rates & Conversions Algebra 1

Rates Rate – two quantities measured in different units. Unit rate – a rate per one given unit For example, 30 mph

Example 1 Find the Unit Rate $2 for 5 cans of green beans

Ex. 2 Convert the measure. 12 fluid ounces to cups (1 cup = 8 fluid ounces)

Ratio A ratio is a comparison of two numbers by division. The ratio of 2 to 5 can be expressed three different ways; 2 to 5 2:5 2/5

Ratio’s (cont’d) Basically, a ratio has to be a comparison of only like things or labels (in., ft., yd., & mile) Referring to our previous example, then 2 ft to 5 ft we can write as a ratio, 2:5. If we had 3 ft. to 7 in., then we would have to change feet to inches first. 3 • 12 = 36 36 in. to 7 in. OR 36/7

Ex. 3 The Sears tower in Chicago, Illinois, is 1450 ft. tall. About how many meters tall is the tower? Use the fact that 1m is approximately 3.28 ft.

Assignment

Percent A percent is a ratio that compares a number to 100. Percent also means per hundred, or hundredths. Percents can be expressed with a percent symbol (%), as fractions, or as decimals. 35% = 35/100 = .35

To solve problems with percents, you can either use PERCENT PROPORTION OR Percentage = r Base 100 **Choose the best way EQUATIONS Write equations based on the key words, is = of x what no. n

Example 1 30 is what percent of 70? 70 100 **What percent of 70 is 30? 30 = n * 70

Example 2 What number is 36% of 112? 112 100 n= .36 * 112