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December 6, 2011

December 6, 2011. 1) Write your homework in your agenda: Ratios/Missing Numbers in Ratios wksh (f/b) 2) Take out your quiz, make sure your name is on it and pass it forward. 3) Take out a piece of loose leaf paper and set it up for Cornell Notes. Ratio and Proportion.

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December 6, 2011

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  1. December 6, 2011 1) Write your homework in your agenda: Ratios/Missing Numbers in Ratios wksh (f/b) 2) Take out your quiz, make sure your name is on it and pass it forward. 3) Take out a piece of loose leaf paper and set it up for Cornell Notes.

  2. Ratio and Proportion What am I Learning Today? How will I show that I learned it? Write ratios in three ways using the correct order to accurately represent quantitative relationships Write and solve problems using proportional reasoning

  3. Questions Notes Questions Answers • 3 ways: • As a fraction: 1/2 • With the word “to”: 1 to 2 • - With a colon (:): 1:2 How do I write a ratio? ** KEEP THINGS IN ORDERWhen working with ratios keep the numbers in the same order as they are given. What do ratios compare? - part to part (boys to girls) - part to whole (boys to total students) - whole to part (total students to girls) What are equivalent ratios? Ratios that name the same comparison How do I create equivalent ratios? Just like equivalent fractions

  4. 29 12 29 ___ ___ 12 12 29 For a time, the Boston Symphony Orchestra was made up of 95 musicians. For example, you can use a ratio to compare the number of violins (29) with the number of violas (12). This ratio can be written in three ways: 29 to 12, 29:12, or Notice that the ratio of violins to violas, is different from the ratio of violas to violins, . The order of the terms is important.

  5. Use the table to write each ratio. 1.giraffes to monkeys 2. polar bears to all bears 3. monkeys to all animals 4. all animals to all bears 2:17 4:7 17:26 26:7 http://my.hrw.com/math06_07/nsmedia/lesson_videos/msm1/player.html?contentSrc=6993/6993.xml

  6. Let’s hear it another way…. • http://www.learnalberta.ca/content/mesg/html/math6web/math6shell.html#

  7. 3 4 2 n __ __ __ __ = 5 15 4 8 Questions Answers How do I know if ratios are proportionate? 1) If possible, treat like equivalent fractions. = 2) If not, use cross products to solve for the missing information. Two ratios are proportionateif their cross products are equal. Find the cross products. The cross products are set equal to each other. 5 •n= 3 • 15 5n= 45 Divide both sides by 5 to undo the multiplication. n = 9

  8. 5 6n 90 n __ __ ___ ___ = 6 18 6 6 Using Cross Products to Complete Proportions Find the missing value in the proportion. Find the cross products. 6 •n= The cross products are equal. 5 • 18 6n= 90 n is multiplied by 6. Divide both sides by 6 to undo the multiplication. = n = 15

  9. Solving Proportions • Find the missing value in each proportion. n = 2 n = 6 n = 14

  10. Student Summary Spotlight

  11. 4:2 4 to 2

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