1. Section 3-4: Ratio and Proportion Objectives: 1)To find ratios and rates 2)To solve proportions

2. Definitions Ratio: A relationship between two numbers through division Rate: In a ratio, when each term represents a quantity measured in different units Unit Rate: a rate with a denominator of 1. Unit Analysis: The process of converting from one unit to another Proportion: An equation that states that two ratios are equal Extremes of the Proportion: the numerator the 1 st ratio and the denominator of the 2 nd ratio. Means of the Proportion: the numerator of the 2 nd ratio and the denominator of the 1 st ratio

3. Cross Product Property If, then Ex: Since 24 = 24, we know that the proportion is valid extremes means

4. Unit Pricing …In Real Life

5. Example: Using Unit Rates The table below gives prices for different sizes of the same brand of apple juice. Find the unite rate (cost per ounce) for each. Which has the lowest cost per ounce? PriceVolume $0.7216 oz $1.2032 oz $1.6064 oz

6. Using Unit Rates Divide This has the lowest cost per ounce.

7. Real-World Example In 2004, Lance Armstrong won the Tour de France, completing the 2291 km course in about 83.6 hours. Find Lance’s unit rate, which is his average speed. Write a rule to describe the distance he cycles d as a function of the time t he cycles. Cycling at his average speed, about how long would it take Lance to cycle 185km?

8. Real-World Example Distance  Time 

9. Another Cross Product Example Solve the proportion