Transcript Ratios
Video Clip Click on the line below to view the video about ratios http://www.youtube.com/watch?v=HpdMJaKaXXc&fe ature=relmfu Vocabulary Review Ratio is a comparison of two quantities by division Ratios can be written in three ways: 2 1. As a fraction 3 2. With the word “to” in between numbers 2 to 3 3. Or with a colon 2 : 3 Writing Ratios A way of comparing one quantity to another Ex. A bag of miniature chocolate bars has 12 dark chocolate, and 14 milk chocolate candy bars. Write each ratio in all three forms comparing the number of dark chocolate bars to milk chocolate As a fraction 12 14 With a colon 12:14 With the word “to” 12 to 14 Simplifying Ratios Just like fractions, ratios must be simplified Ex. A package of Starburst candy has two lemon, three strawberry, three cherry, and four orange Write a ratio comparing the number of orange candies to the number of lemon candies in the package 4/2 simplifies to 2/1 or 2:1 or 2 to 1 Let’s Practice Simplify the ratio of collies to boxers 22: 28 22/28 ÷ 2 = 11/14 Simplify the ratio of poodles to boxers 18: 28 18/28 ÷ 2 = 9/14 Simplify the ratio of poodles to collies 18:22 18/22 ÷ 2 = 9/11 Writing Ratios A basket of fruit has 2 apples, 6 grapes, 3 bananas, and 4 oranges Write a ratio comparing the number of apples to the number of grapes 2 to 6 or 2:6 or 2/6 Simplify your ratio by dividing by 2; simplified ratio is 1 to 3 or 1:3 or 1/3 Let’s Practice The annual dog show has 22 collies, 28 boxers, and 18 poodles Write the ratio of collies to poodles Write the ratio of poodles to boxers Write the ratio of boxers to poodles Write the ratio of collies to boxers Comparing Ratios When comparing ratios, you must have a common denominator so that you can compare the numerators Ex. 3/5 and 2/10 Find the common denominator between 5 and 10 So 3/5 = 6/10 Now, you can compare 2/10 to 6/10 Comparing Ratios Tell whether the wallet size photo or the portrait size photo has the greater ratio of width to length by using the table to write a ratio for each Write the ratios so you can compare Length Width Wallet 3 5 Personal 4 6 Desk 5 6 Portrait 8 10 Comparing Ratios Wallet : Portrait comparing Width to Length 3: 5 compared to 8:10 Rewrite as a fraction: 3/5 and 8/10 Find common denominator (10) Rewrite 3/5 as 6/10 and compare to 8/10 Portrait size has the greater ratio of width to length Comparing Part to Part Ratios can compare part to part Ex. Number of Krackel bars to the number of milk chocolate bars in the package 9 milk, 6 dark, 3 Mr. Goodbar, and 6 Krackel 6 to 9 or 6:9 or 6/9 Write in the simplest form: 6/9 ÷ numerator & denominator by 3 = 2/3 or 2:3 or 2 to 3 Let’s Practice Compare the number of girls to the number of boys in the class Write the ratio in three different ways Be sure to simplify the ratio if necessary Comparing Part to Whole Ratios can also compare one specific part to the whole Ex. Number of dark chocolate bars to the total number of candy bars in the package 9 milk, 6 dark, 3 Mr. Goodbar, and 6 Krackel 6 to 24 or 6:24 or 6/24 Write in simplest terms: 6/24 ÷ numerator & denominator by 6 = 1/4 or 1 to 4 or 1:4 More Practice Compare the number of boys to the total number of students in the class Write the ratio in three different ways Be sure to simplify the ratio if necessary Compare the number of girls to the total number of students in the class Write the ratio in three different ways Be sure to simplify the ratio if necessary