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8-1: Ratios and Equivalent Ratios. IWBAT read and write ratios and equivalent ratios. Ratio – A comparison of two quantities. 9 girls and 7 boys. Three ways to write ratios:. 9:7 9 to 7. Ratio. Two ratios that are equal to each other. Equivalent Ratios. 5:8 _____ 15:24.
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8-1: Ratios and Equivalent Ratios IWBAT read and write ratios and equivalent ratios
Ratio – A comparison of two quantities 9 girls and 7 boys Three ways to write ratios: 9:7 9 to 7 Ratio
Two ratios that are equal to each other Equivalent Ratios
5:8 _____ 15:24 1) Rewrite as in fraction form and make equal to each other 120 = 120 2) Cross-multiply (multiply diagonally) 3) If cross-products are equal, the ratios are equivalent (=). If cross-products are not equal () Are the ratios equivalent?
1) 2) 3) 9 to 8 ____ 45 to 40 108 = 108 8096 360 = 360 Examples
8-2 and 8-3: Proportions IWBAT solve proportions using equivalent ratios using Cross-Products (Cross-Multiplication)
Use the cross-multi plying method 60 = 60 Yes Do these ratios make a proportion?
1) 2) 3) 54 = 54 320 = 320 63 72 Yes Yes No Examples
1) Simplify vertically and/or horizontally, if possible 2) Cross-multiply 3) Solve for , if needed Find the missing number
1) 2) 3) 4) 5) Three boxes of cereal cost $10.50. What does one box cost? Examples
8-4: Too Much or Too Little Information IWBAT determine which information is missing and identify extraneous information in problems.
8-5: Rates IWBAT use rates to solve problems.
Rate – A ratio that compares two quantities that have different units of measure • Unit Rate – A rate where the second quantity is a unit of one (denominator) Vocabulary
You travel 99 miles in 90 minutes. What is your average rate of speed in miles per hour? 1) Write as a rate in fraction form 2) Divide 9.5 3) Rewrite as a phrase or as a fraction with labels 9.5 miles per minute Find the Unit Rate
1) 90 miles in 75 minutes 2) 252 miles every 9 gallons 3) 48 chairs for 6 tables 4) 96 students in 3 classrooms 5) Respiration rate is the number of breaths you take per minute. You count 48 breaths in 3 minutes and your friend counted 34 breaths in 2 minutes. Who had the higher respiration rate? Examples
8-6: Unit Price IWBAT find unit prices to determine the better buy.
Unit Price – The cost per item • Similar to unit rate but money amount always is the numerator • Round to the nearest cent (hundredth), if necessary Vocabulary
Find the unit price. Round to the nearest cent. $60.00 for 12 books 1) Write as a rate in fraction form with the price in the numerator 2) Divide $5 3) Rewrite as a phrase or as a fraction with labels $5 per book Unit Price
1) $46.20 for 6 shirts 2) $14.28 for 12 lb of turkey 3) $1.47 for 1.5 lb broccoli 4) $0.60 for 12 oz of rolls Examples
12 bananas for $1.80 or 15 bananas for $2 1) Find the unit price for each item. 2) Compare. The better buy is the cheaper (lesser) amount. 15 bananas for $2 is the better buy. Which is the better buy?
1) 3 tacos for $3.50 or 4 tacos for $5.00 2) 12 books for $119.40 or 6 books for $53.34 Examples
8-7: Make a List IWBAT solve problems by making an organized list
8-8: Similar Figures IWBAT use proportions to solve problems involving similar figures
Similar Figures – Figures that have the same shape but not necessarily the same size. Vocabulary
8-9: Scale Drawings IWBAT interpret scale drawings.
Scale Drawing – a reduction or enlargement of an actual object. • Scale – a ratio that compares a measure on a drawing with the actual measure. Vocabulary
8-10: Using Maps IWBAT use map scales and proportions to find actual distances