Original Test Question A Determine which pair of ratios does NOT form a proportion. A) B) and C) and D. and and Method 2: Convert each ratio to a decimal. Both ratios will equal the same decimal value if they form a proportion. For example: 30/75= .4 and 8/20 = .4 So does form a proportion. Method 1: Check the cross products. Cross products of proportions are always equal. For example: 30(20)=600 and 8(75)=600 So does form a proportion.

Do the following pairs of ratios form proportions? Now try these! Do the following pairs of ratios form proportions? 9(20)=180 and 6(27)=162 So they do not form a proportion 12(3)=36 and 8(4.5)=36 So they do form a proportion

Original Test Question B Use a proportion to determine whether or not the two candy bars below contain an equal proportion of sugar. Snickers: A 59 gram candy bar contains 30 grams of sugar. Milky Way: A 72 gram candy bar contains 35 grams of sugar. Since the cross products are not equal the bars do not Contain an equal proportion of sugar!

Now try this! Use a proportion to determine whether or not the two bags of potato chips below contain an equal proportion of carbs. Lays: A 40 gram bag contains 14 grams of carbs. Ruffles: A 60 gram bag contains 21 grams of carbs. Since the cross products are equal the bags contain an equal proportion of carbs!

Original Test Question C A 12 ounce can of Coke costs $0.75 when purchased from the soda machine at the school. An 18 ounce bottle of Pepsi from the soda machine at the local gas station costs $1.25. Find the unit cost of each to determine which location has the less expensive soda per ounce? Coke Pepsi Coke is the better deal because it is $.01 cheaper per ounce

Now try this! A 20 ounce bag of potato chips costs $3.99 at the store. The same brand of chips costs $.50 for 3 oz in the vending machine. Find the unit price for each ounce and determine the better deal. Store Vend The vending machine has the better deal because those chips cost 3 cents more per ounce.

Original Test Question D The ratio of teachers to students in the gym is 2 to 9. How many teachers are in the gym if there is a total of 165 students and teachers altogether in the gym? The problem tells you that in the ratio there are 2 teachers To every 9 students. Next, it gives you the total number of 165. This means you need the total in the ratio of 9+2=11

Now try this! The ratio of fish to snails in an aquarium is 4 to 5. How many fish are in the aquarium if there is a total of 117 fish and snails altogether in the aquarium?

Original Test Question E Which ratio is equivalent to ? You can simplify each ratio or change each ratio to a decimal to compare. Both and simplify to or .75 so they are equivalent

Now try this! You can simplify each ratio or change Which ratio is equivalent to ? You can simplify each ratio or change each ratio to a decimal to compare. Both and simplify to or .4 so they are equivalent