Ratio – comparing same things 2 apples to 4 apples 2 apples / 4 apples 2 apples : 4 apples Rate – comparing different things 2 apples to 4 basketballs 2 apples / 4 basketballs 2 apples : 4 basketballs

Unit Rate – comparing different things – (the denominator is always one) 2 apples to 1 cat 2 apples / 1 cat 2 apples : 1 cat Unit Cost or Price – comparing different things – (the denominator is always one & the money always comes first) $2 to 1 ounce $2 / 1 ounce $2 : 1 ounce

Example 1: Determine whether the following ratios form a proportion. a.) b.) Yes, because cross products are equal 60 = 60 No, because cross products are not equal 10 = 8

Example 2: Solve each proportion below by using the cross products. a.) b.) c.) d.) Algebra Method: 2x = 90 Divide by 2 on both sides x = 45 Algebra Method: 12x = 84 Divide by 12 on both sides x = 7 Baby Math Method: (9*10)/2 Baby Math Method: (4*21)/12 Algebra Method: 15x = 180 Divide by 15 on both sides x = 12 Algebra Method: 8x = 72 Divide by 8 on both sides x = 9 Baby Math Method: (12*6)/8 Baby Math Method: (20*9)/15

Example 3: Set up a proportion for each scenario below and solve by doing the cross products. a.) Andy paid $1.29 for 3 pieces of candy. At that rate, what would 8 pieces of candy cost? b.) You are visiting friends in Estonia. Suppose the exchange rate is 12.68 kroons = 1 dollar. How many Estonia kroons will you receive if you have $500? x = $3.44 Dollars Candy Kroons Dollar x = $6340