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How do you use proportions to convert measurements, find the unknown side length of polygon or real life objects, and interpret and construct scale models?

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We can also use cross products to solve proportions to convert units. In order to do this we must know the units, though. Please copy the following two slides neatly into your work. You will be quizzed separately on each set of information.

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Length: 12 inches = 1 foot 3 feet = 1 yard 5280 yards = 1 mile Weight: 16 oz = 1 lb 2000 lb = 1 ton Capacity 8 fl oz = 1 cup 2 cups = 1 pint 2 pints = 1 quart 4 quarts = 1 gallon

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1 millimeter = 0.001 meter 1 centimeter = 0.01 meter 1 decimeter = 0.1 meter 1 meter 1 dekameter = 10 meters 1 hectometer = 100 meters 1 kilometer = 1,000 meters

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To analyze units we will be given a value in one unit and be told to change it into a different unit. We will set these units as a ratio. We will set that ratio equal to a ratio from our measurement notes. We will solve for the missing value. Make sure that the units match in each ratio.

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The average American eats 23 pounds of pizza per year. Find the number of ounces of pizza the average American eats per year. 23 lb x oz We know 16 oz = 1 lb. Set up a proportion 23 lb = 1 lb x oz 16 oz Cross multiply: 23 16 = 1x Simplify: 368 oz

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Aihua drinks 4 cups of water a day. Find the total number of fluid ounces of water she drinks per day. 4 cups x fl oz 8 fl oz = 1 cup ~ Set up a proportion 4 cups = 1 cup x fl oz 8 fl oz Cross multiply: 4 8 = 1x Simplify: 32 fl oz

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A model airplane flies 22 feet in 2 seconds. How many inches did the airplane fly? 22 ft x in 12 inches = 1 foot ~ set up proportion 22 ft = 1 ft x in 12 in Cross multiply: 22 12 = 1x Simplify: 264 inches

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A fish swims 13 centimeters. How many meters did the finish swim? 13 cm x m 1 cm = 0.01 m ~ set up a proportion 13 cm = 1 cm x m 0.01m Cross multiply: 13 0.01 = 1x Simplify = 0.13 m

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8 gallons equals how many quarts? 8 gal x qt 4 quarts = 1 gallon 8 gal = 1 gal x qt 4 qt Cross multiply: 8 4 = 1x Simplify 32 quarts

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