1. PODPOD advanced Kobe runs from baseline to baseline (94ft) in 4 seconds to score the game winning basket. How many miles per hour does he run? basic 25 miles 2 hours = _____ ft/hr 66,000 ft 1 hour 16 miles 1 hour

2. 4-3 Proportions A proportion is an equation stating that two ratios are equal. Key Concepts Arithmetic 1 = 2 2 4 a = c b d Algebra

3. One method of testing whether ratios form a proportion is to write both ratios in simplest form, then see if they are equal. I do: 10 24 25 60 ÷2 ÷5 5 12 5 12 Since both ratios are equal to 5/12, they form proportion

4. Let’s try it together. We do: 42 56 64 ÷7 ÷8 6 8 7878 The ratios in simplest form are not equivalent. They do not form a proportion. Example 1

5. Quick Check 1 You do: 10 12 40 56 ÷2 ÷8 5 6 5757 The ratios in simplest form are not equivalent. They do not form a proportion. Do 10/12 and 40/56 form a proportion?

6. Cross Products Property Cross products are the two products found by multiplying the denominator of each ratio by the numerator of the other ratio. Arithmetic 6 = 9 8 12 a = c b d Algebra 6×12 = 8×9ad = bc If two ratios form a proportion, the cross products are equal. If two ratios have equal cross products, they form a proportion. Key Concepts

7. I do: 6868 9 12 8×9 = 6×12 72 = 72 Since the cross-products are equal, the ratios form a proportion.

8. Let’s try it together. We do: Example 2 4 6 10, 15 a. b. 8 9 6, 7 10×6 = 60 4×15 = 60 Does form a proportion 8×7 = 56 6×9 = 54 Does not form a proportion

9. Quick Check 2 You do: Determine whether the ratios form a proportion 3 6 8, 16 a. 6 4 9, 6 b. 4 5 8, 9 c. Does form a proportion Does not form a proportion