Warm Up Problem of the Day Lesson Presentation Lesson Quizzes 1

1. jump rope 192 times in 6 minutes Warm Up Find each unit rate. 1. jump rope 192 times in 6 minutes 2. four pounds of bananas for $2.36 3. 16 anchor bolts for $18.56 4. 288 movies on 9 shelves 32 jumps/min $0.59/lb $1.16/bolt 32 movies/shelf 2

Problem of the Day The sum of four consecutive integers is 182. What are the four numbers? 44, 45, 46, and 47 3

Sunshine State Standards MA.7.G.4.4 Compare, contrast, and convert units of measure between different measurement systems (US customary or metric (SI)), dimensions, and derived units to solve problems.

Vocabulary unit conversion factor 5

A unit conversion factor is a fraction in which the numerator and denominator represent the same quantity in different units. 6

Additional Example 1: Using Conversion Factors to Solve Problems The average American uses 580 pounds of paper per year. Find this rate in pounds per month, to the nearest tenth. The problem gives the ratio 580 pounds to 1 year and asks for an answer in pounds per month. 580 lb 1 yr 1 yr 12 mo Multiply the ratio by the conversion factor. Cancel yr units. • yr mo = lb 580 lb 12 mo = = 48.3 lb per month Divide 580 by 12. The average American uses 48.3 pounds of paper per month. 7

Check It Out: Example 1 Sam drives his car 23,040 miles per year. Find this rate in the number of miles driven per month, to the nearest mile. 23,040 miles 1 yr 1 yr 12 mo = 1,920 mi/mo 8

Additional Example 2: Converting Between Metric and Customary Units One mile is about 1.6 kilometers. What is the length in miles of a 10 kilometer race? Round to the nearest tenth of a mile. miles kilometers Write a proportion using 1 mi. = 1.6 km. 1 1.6 x 10 = The cross products are equal. 1 · 10 = 1.6 · x 10 = 1.6x Multiply. ___ ___ 1.6 1.6 Divide each side by 1.6. 6.25 = x A 10 kilometer race is about 6.3 miles. 9

Check It Out: Example 2A One inch is equal to 2.54 centimeters. How many inches are there in 12 centimeters? Round to the nearest tenth. ; 2.54 1 12 x 2·54x = 12; x ≈ 4.7; 4.7 in. = 10

Check It Out: Example 2B One gallon is equal to about 3.875 liters. How many liters are there in 6 gallons? Round to the nearest tenth. ; 3.875 1 x 6 x= 6 3.875 = 23.25; 23.3 L = 11

Additional Example 3: Application A tennis pro serves a ball that travels the length of the court, 78 feet, in 0.75 second. How fast is the ball moving in feet per second? Check your answer for reasonableness. 12

Additional Example 3 Continued The ball’s speed is 104 ft/s. Convert ft/s to mi/h to see if the answer is reasonable. The ball’s average speed is 71 mi/h, which is a reasonable speed for a serve. 13

Check It Out: Example 3 Gary travels 1,320 ft in 1.5 min on his bicycle. How fast is he traveling in feet per min? Check your answer for reasonableness. 1,320 ft 1.5 min = 1,320 ft ÷ 1.5 1.5 min ÷ 1.5 880 ft 1 min 14

Check It Out: Example 3 Continued Convert to mi/hr: 880 ft 1 min = 60 min 1 hr 5280 ft 10 min hr This is a reasonable speed for a bicycle. 15

Lesson Quizzes Standard Lesson Quiz Lesson Quiz for Student Response Systems

Find the appropriate factor for each conversion. Lesson Quiz Find the appropriate factor for each conversion. 1. You drive 136 miles from your house to your aunt’s house at the lake. You use 8 gallons of gas. How many yards does your car get to the gallon? 2. One ounce is about 28.3 grams. A box of cereal has a mass of 400 grams. What is the weight of the box in ounces? Round to the nearest tenth of an ounce. 29,920 yd gal 14.1 oz 17

Find the appropriate factor for each conversion. Lesson Quiz Find the appropriate factor for each conversion. 3. A cheetah was timed running 200 yards in 6 seconds. What was the average speed in miles per hour? ≈ 68 mi/h 18

Lesson Quiz for Student Response Systems 1. A recipe for lemonade requires diluting the lemonade concentrate with 6 quarts of water. How many gallons of water are required to dilute the concentrate? A. 1 gallon B. 1.5 gallons C. 2 gallons D. 2.5 gallons

Lesson Quiz for Student Response Systems 2. There are about 400 jelly beans in a pound. There are 2.2 pounds in a kilogram. About how many grams does a jelly bean weigh? A. 0.85 g B. 0.98 g C. 1.06 g D. 1.14 g

Lesson Quiz for Student Response Systems 3. A sea horse swims at about 0.01 miles per hour. What is the swim speed in inches per second? A. 10.56 inches per second B. 10.75 inches per second C. 11.24 inches per second D. 11.5 inches per second