1. Date: 9.1 Notes: Ratios and Proportions Lesson Objective: To write ratios and write and solve proportions CCSS: G.MG.3

2. Lesson 1: Writing Ratios

3. A.In 2013, Joey Chestnut ate 69 hotdogs in 10 minutes at the Nathan’s Famous International Hot Dog Eating Contest. That is still the current record! Ratio: ___ hotdogs minutes

4. Lesson 1: Writing Ratios Ratio: A comparison of 2 numbers by divi- sion; can be written a to b, a:b, or a / b, where b ≠ 0.

5. Lesson 1: Writing Ratios B.In 2012, Joey ate 68 hotdogs in 10 minutes. Write the ratio.

6. Lesson 1: Writing Ratios C.Write a ratio expressing the slope of line t containing the points A(1,-2) and B(-3, 4). Slope = m = y 2 – y 1 = – ( ) = = x 2 – x 1 –

7. Lesson 2: Using Ratios A ratio can involve more than 2 num­bers. The ratio of the side lengths of a quad­ rilateral is 2:3:5:7 and its perimeter is 85 cm. What is the length of the longest side?

8. Lesson 3: Cross Product Property Proportion: An equation stating that 2 ratios are equal. Cross Product Property: extrememean If a = c b d mean extreme and b and d ≠ 0, then ad = bc.

9. Lesson 3: Solving Proportions A.If Joey Chestnut ate 69 hotdogs in 10 minutes, how many would he have eaten in 1 hour at that rate (1 hr = 60 min.)? 69 hot dogs = x hot dogs 10 minutes 60 minutes

10. Lesson 3: Solving Proportions B.Solve. x + 2 = 24 6 x + 2

11. Lesson 3: Properties of Proportions Equivalent Proportions: a = c or b = d or a = b  ad = bc b d a c c d

12. Lesson 4: Using Properties of Proportions A.Given that 4x = 10y, find the ratio of x to y in simplest form.

13. Lesson 4: Using Properties of Proportions B. During the filming of The Lord of the Rings, the special-effects team built a model of Sauron’s tower with a height of 8 m and a width of 6 m. If the width of the full-size tower is 996 m, what is the height?

14. 9.1: Do I Get It? Yes or No 1.Here at CHHS, we have 125 teachers and approximately 3000 students. What is the student-teacher ratio? 2.The ratio of the mea- sures of the angles in a triangle is 3:4:5. Find the measures of the angles.

15. 9.1: Do I Get It? Continued 3.Solve each proportion. 4.Fernando conducted a survey of 50 students driving to school and found that 28 owned cars. If 755 students drive to his school, predict the total number of students who own cars.