# Tues 96 SWBAT calculate ratio and proportion problems

Tues, 9/6 SWBAT… calculate ratio and proportion problems Agenda 1. WU (10 min) 2. Notes on ratios & proportions – 2 slides (15 min) 3. Practice problems – 3 examples (10 min) 4. Work on HW#9 (10 min) WU: Solve each equation (show all your work!): 1. 2. 3. 4. HW#8 -Ratio & Proportions

Topic: Ratios and Proportions n Definition: A ratio is a comparison of two numbers by division. Picture: The ratio of x to y can be expressed in the following ways: x to y, x: y, n Examples: 3 to 7, 3: 7, n

Proportion n Definition: A proportion is an equation that states two ratios are equal. n Picture/Example: n To determine whether pairs of ratios are equivalent, use cross products Or, cross multiply n (7)(48) = (42)(8) 336 = 336 n The cross products are equal, so the ratios do form a proportion and therefore the pair of ratios are equivalent. (Prob #2 on the HW#9)

Directions: Solve the proportion. n Example 1: n(27) = 6(9) 27 n = 54 n=2 (Prob #4 on the HW#9)

Example 2: 1. Write a proportion with one unknown variable. 2. Solve for the unknown variable. n

` Example 2: n A restaurant made $545 in profit from selling 110 hamburgers. If they sold 53 hamburgers during lunch, what was their profit? n

Wed, 9/7 SWBAT… calculate ratio, proportions, time, and conversions Agenda 1. Quiz (10 min) 2. Time conversions (30 min) Quiz: Complete on a sheet of paper (collected) Solve each proportion: 1. 2. 3. Mr. V can run 10 miles in 1. 5 hours, how long (in hours and minutes) will it take him to run a marathon (26 miles) at the same speed. HW#9 -Time conversions

HW#9 Answers 1. 2. 3. 4. 5. 6. 7. No Yes No n=2 u=5 b = 3. 75 t = 0. 57

- Slides: 8