7.5 Systems of Measurement

Learning objectives

Learning objectives

• Make unit conversions in the U.S. system

• Use mixed units of measurement in the U.S. system

• Make unit conversions in the metric system

• Use mixed units of measurement in the metric system

• Convert between the U.S. and the metric systems of measurement

• Convert between Fahrenheit and Celsius temperatures

In this section we will see how to convert among different types of units, such as feet to miles or kilograms to pounds. The basic idea in all of the unit conversions will be to use a form of $1,$ the multiplicative identity, to change the units but not the value of a quantity.

Make Unit Conversions in the U.S. System

There are two systems of measurement commonly used around the world. Most countries use the metric system. The United States uses a different system of measurement, usually called the U.S. system. We will look at the U.S. system first.

The U.S. system of measurement uses units of inch, foot, yard, and mile to measure length and pound and ton to measure weight. For capacity, the units used are cup, pint, quart and gallons. Both the U.S. system and the metric system measure time in seconds, minutes, or hours.

The equivalencies among the basic units of the U.S. system of measurement are listed in Table 7.2. The table also shows, in parentheses, the common abbreviations for each measurement.

Table

7.2

In many real-life applications, we need to convert between units of measurement. We will use the identity property of multiplication to do these conversions. We’ll restate the Identity Property of Multiplication here for easy reference.

To use the identity property of multiplication, we write $1$ in a form that will help us convert the units. For example, suppose we want to convert inches to feet. We know that $1$ foot is equal to $12$ inches, so we can write $1$ as the fraction $\frac{\mathrm{1 ft}}{\mathrm{12 in}}.$ When we multiply by this fraction, we do not change the value but just change the units.

But $\frac{\mathrm{12 in}}{\mathrm{1 ft}}$ also equals $1.$ How do we decide whether to multiply by $\frac{\mathrm{1 ft}}{\mathrm{12 in}}$ or $\frac{\mathrm{12 in}}{\mathrm{1 ft}}?$ We choose the fraction that will make the units we want to convert from divide out. For example, suppose we wanted to convert $60$ inches to feet. If we choose the fraction that has inches in the denominator, we can eliminate the inches.

On the other hand, if we wanted to convert $5$ feet to inches, we would choose the fraction that has feet in the denominator.

We treat the unit words like factors and ‘divide out’ common units like we do common factors.

Example 7.44

Solution

1. Choose the unit identity. Since $1$ foot equals $12$ inches, $\frac{1\ \mathrm{foot}}{12\ \mathrm{inches}}$ is a conversion factor equal to $1$.
2. Multiply by the identity. Compute $66\ \mathrm{inches}\cdot\frac{1\ \mathrm{foot}}{12\ \mathrm{inches}}$.
3. Cancel the inch units. The inches in the numerator and denominator divide out, leaving $\frac{66}{12}$ feet.
4. Finish the division. Since $\frac{66}{12}=5.5$, Mary Anne is $5.5$ feet tall.

Takeaway: Because $12$ inches equal $1$ foot, multiplying $66$ inches by $\frac{1\ \mathrm{foot}}{12\ \mathrm{inches}}$ cancels the inch units and gives $5.5$ feet.

When we use the Identity Property of Multiplication to convert units, we need to make sure the units we want to change from will divide out. Usually this means we want the conversion fraction to have those units in the denominator.

Example 7.45

Solution

1. Choose the conversion identity. Because $1$ ton equals $2000$ pounds, $\frac{2000\ \mathrm{pounds}}{1\ \mathrm{ton}}$ is a factor equal to $1$.
2. Multiply the measurement by that identity. Compute $3.2\ \mathrm{tons}\cdot\frac{2000\ \mathrm{pounds}}{1\ \mathrm{ton}}$.
3. Cancel the ton units. The unit tons cancels, leaving $3.2\cdot2000$ pounds.
4. Multiply the numerical factors. Since $3.2\cdot2000=6400$, Ndula weighs almost $6400$ pounds.

Takeaway: Using $1$ ton equals $2000$ pounds, $3.2$ tons converts to $3.2\cdot2000=6400$ pounds.

Sometimes to convert from one unit to another, we may need to use several other units in between, so we will need to multiply several fractions.

Example 7.46

Solution

1. Choose the conversion factors. Use the unit factors $\frac{7\ \mathrm{days}}{1\ \mathrm{week}}$, $\frac{24\ \mathrm{hours}}{1\ \mathrm{day}}$, and $\frac{60\ \mathrm{minutes}}{1\ \mathrm{hour}}$ to connect the units.
2. Set up the product. Multiply $9\ \mathrm{weeks}$ by all three factors: $9\ \mathrm{weeks}\cdot\frac{7\ \mathrm{days}}{1\ \mathrm{week}}\cdot\frac{24\ \mathrm{hours}}{1\ \mathrm{day}}\cdot\frac{60\ \mathrm{minutes}}{1\ \mathrm{hour}}$.
3. Cancel and multiply. The week, day, and hour units cancel, leaving $9\cdot{}7\cdot{}24\cdot{}60$ minutes. Computing gives $63\cdot{}24=1512$ hours and $1512\cdot{}60=90720$ minutes, matching the cancellation shown in the figures.
4. State the result. The time is $90720$ minutes.

Takeaway: Choose conversion factors in the order that lets adjacent units cancel, and keep the desired unit until the end.

Example 7.47

Solution

1. List the chained unit identities. Use $\frac{4\ \mathrm{quarts}}{1\ \mathrm{gallon}}$, $\frac{2\ \mathrm{pints}}{1\ \mathrm{quart}}$, $\frac{2\ \mathrm{cups}}{1\ \mathrm{pint}}$, and $\frac{8\ \mathrm{fluid\ ounces}}{1\ \mathrm{cup}}$.
2. Multiply the factors by $1$ gallon. The product is $1\ \mathrm{gallon}\cdot\frac{4\ \mathrm{quarts}}{1\ \mathrm{gallon}}\cdot\frac{2\ \mathrm{pints}}{1\ \mathrm{quart}}\cdot\frac{2\ \mathrm{cups}}{1\ \mathrm{pint}}\cdot\frac{8\ \mathrm{fluid\ ounces}}{1\ \mathrm{cup}}$.
3. Cancel each old unit. Gallon, quart, pint, and cup cancel in turn, leaving the numerical factor $4\cdot2\cdot2\cdot8$ fluid ounces.
4. Compute the product. Since $4\cdot2\cdot2\cdot8=128$, there are $128$ fluid ounces in $1$ gallon.

Takeaway: Chaining the conversion factors from gallons to quarts, pints, cups, and fluid ounces gives $4\cdot2\cdot2\cdot8=128$ fluid ounces per gallon.

Use Mixed Units of Measurement in the U.S. System

Performing arithmetic operations on measurements with mixed units of measures requires care. Be sure to add or subtract like units.

Example 7.48

Solution

1. Convert to a common unit. Since $1\ \mathrm{pound}=16\ \mathrm{ounces}$, the three steak weights are $14$ ounces, $16+2=18$ ounces, and $16+6=22$ ounces.
2. Add the ounce measures. The total is $14+18+22=54$ ounces. This agrees with the figure, which records $2$ pounds $22$ ounces for the last two steaks together and shows the remaining $14$ ounces to be added.
3. Convert the total back to pounds. Divide $54$ by $16$: $54=3\cdot{}16+6$, so the total is $3$ pounds with $6$ ounces remaining.
4. State the result. Charlie bought $3$ pounds $6$ ounces of steak in total.

Takeaway: Add mixed measurements only after converting them to one common unit, then carry any group of $16$ ounces into a pound.

Example 7.49

Solution

1. Multiply each unit part. Four planks of $6$ feet give $4\cdot{}6=24$ feet, and four lengths of $4$ inches give $4\cdot{}4=16$ inches.
2. Normalize the inches. Since $16$ inches equals $1$ foot $4$ inches, the $24$ feet $16$ inches shown in the figure becomes $25$ feet $4$ inches.
3. State the result. Placed end-to-end, the four planks measure $25$ feet $4$ inches in total.

Takeaway: For a product of mixed units, multiply each unit separately and then carry the inch group into feet.

Make Unit Conversions in the Metric System

In the metric system, units are related by powers of $10.$ The root words of their names reflect this relation. For example, the basic unit for measuring length is a meter. One kilometer is $1000$ meters; the prefix kilo- means thousand. One centimeter is $\frac{1}{100}$ of a meter, because the prefix centi- means one one-hundredth (just like one cent is $\frac{1}{100}$ of one dollar).

The equivalencies of measurements in the metric system are shown in Table 7.3. The common abbreviations for each measurement are given in parentheses.

Table

7.3

To make conversions in the metric system, we will use the same technique we did in the U.S. system. Using the identity property of multiplication, we will multiply by a conversion factor of one to get to the correct units.

Have you ever run a $\mathrm{5 k}$ or $\mathrm{10 k}$ race? The lengths of those races are measured in kilometers. The metric system is commonly used in the United States when talking about the length of a race.

Example 7.50

Solution

1. Identify the conversion factor. Use $\frac{1000\ \mathrm{meters}}{1\ \mathrm{kilometer}}$, since $1$ kilometer equals $1000$ meters.
2. Set up the conversion. Multiply $10\ \mathrm{kilometers}$ by this factor: $10\ \mathrm{km}\cdot\frac{1000\ \mathrm{m}}{1\ \mathrm{km}}$.
3. Cancel and multiply. The kilometer units cancel, leaving $10\cdot{}1000=10000$ meters, which is the result illustrated by the conversion figures.
4. State the result. Nick ran $10000$ meters.

Takeaway: In a metric conversion, verify that the original unit cancels and that the remaining unit is the one requested.

Example 7.51

Solution

1. Choose the conversion factor. Use $\frac{1\ \mathrm{kilogram}}{1000\ \mathrm{grams}}$ because $1$ kilogram equals $1000$ grams.
2. Set up the conversion. Multiply $3200\ \mathrm{grams}$ by the factor: $3200\ \mathrm{g}\cdot\frac{1\ \mathrm{kg}}{1000\ \mathrm{g}}$.
3. Cancel and divide. The gram units cancel, leaving $\frac{3200}{1000}$ kilograms, as shown in the final figure. Dividing gives $3.2$ kilograms.
4. State the result. The baby weighed $3.2$ kilograms.

Takeaway: When converting grams to kilograms, divide by $1000$, which is the same as moving the decimal three places to the left.

Since the metric system is based on multiples of ten, conversions involve multiplying by multiples of ten. In Decimal Operations, we learned how to simplify these calculations by just moving the decimal.

To multiply by $10,100,\mathrm{or}\,1000,$ we move the decimal to the right $1,2,\mathrm{or}\,3$ places, respectively. To multiply by $0.1,0.01,\mathrm{or}\,0.001$ we move the decimal to the left $1,2,\mathrm{or}\,3$ places respectively.

We can apply this pattern when we make measurement conversions in the metric system.

In Example 7.51, we changed $3200$ grams to kilograms by multiplying by $\frac{1}{1000}\,(\mathrm{or}\,0.001).$ This is the same as moving the decimal $3$ places to the left.

Example 7.52

Solution

1. State the metric relationships. In the metric table, $1$ kiloliter equals $1000$ liters and $1$ liter equals $1000$ milliliters.
2. Convert $350$ liters to kiloliters. Multiply by $\frac{1\ \mathrm{kiloliter}}{1000\ \mathrm{liters}}$: $350\cdot\frac{1}{1000}=0.35$ kiloliters.
3. Convert $4.1$ liters to milliliters. Multiply by $\frac{1000\ \mathrm{milliliters}}{1\ \mathrm{liter}}$: $4.1\cdot1000=4100$ milliliters.
4. Report both answers. Part ⓐ is $0.35$ kiloliters and part ⓑ is $4100$ milliliters.

Takeaway: Since $1$ kiloliter equals $1000$ liters and $1$ liter equals $1000$ milliliters, $350$ liters is $0.35$ kiloliters and $4.1$ liters is $4100$ milliliters.

Use Mixed Units of Measurement in the Metric System

Performing arithmetic operations on measurements with mixed units of measures in the metric system requires the same care we used in the U.S. system. But it may be easier because of the relation of the units to the powers of $10.$ We still must make sure to add or subtract like units.

Example 7.53

Solution

1. Choose a common unit. Convert the smaller length, $85$ centimeters, into meters before subtracting.
2. Use the metric relationship. Since $1$ meter equals $100$ centimeters, $85$ centimeters is $\frac{85}{100}=0.85$ meters.
3. Subtract the equal-unit lengths. Compute $1.60-0.85=0.75$ meters, aligning the decimal places as shown in the vertical subtraction.
4. State the comparison. Ryland is $0.75$ meters taller than his younger brother.

Takeaway: Converting $85$ centimeters to $0.85$ meters allows the common-unit subtraction $1.60-0.85=0.75$ meters.

Example 7.54

Solution

1. Translate "triple" into multiplication. Tripling means multiplying $150$ milliliters by $3$.
2. Compute the larger amount. Since $3\cdot150=450$, the scaled recipe needs $450$ milliliters.
3. Convert milliliters to liters. Use $\frac{1\ \mathrm{liter}}{1000\ \mathrm{milliliters}}$: $450\cdot\frac{1}{1000}=0.45$ liters.
4. State the amount in the requested unit. Dena needs $0.45$ liter of olive oil.

Takeaway: Tripling $150$ milliliters gives $450$ milliliters, which converts to $0.45$ liters because each liter contains $1000$ milliliters.

Convert Between U.S. and Metric Systems of Measurement

Many measurements in the United States are made in metric units. A drink may come in $\mathrm{2-liter}$ bottles, calcium may come in $\mathrm{500-mg}$ capsules, and we may run a $\mathrm{5-K}$ race. To work easily in both systems, we need to be able to convert between the two systems.

Table 7.4 shows some of the most common conversions.

Table

7.4

We make conversions between the systems just as we do within the systems—by multiplying by unit conversion factors.

Example 7.55

Solution

1. Choose a metric-to-customary factor. Use $\frac{1\ \mathrm{fluid\ ounce}}{30\ \mathrm{milliliters}}$ as a conversion factor equal to $1$.
2. Multiply the bottle capacity. Compute $500\ \mathrm{milliliters}\cdot\frac{1\ \mathrm{fluid\ ounce}}{30\ \mathrm{milliliters}}$.
3. Cancel the milliliters. The milliliter units cancel, leaving $\frac{500}{30}$ fluid ounces.
4. Divide and round to the requested precision. Since $\frac{500}{30}=16.666\ldots$, the bottle holds $16.7$ fluid ounces to the nearest tenth.

Takeaway: Multiplying $500$ milliliters by $\frac{1\ \mathrm{fluid\ ounce}}{30\ \mathrm{milliliters}}$ gives about $16.7$ fluid ounces to the nearest tenth.

The conversion factors in Table 7.4 are not exact, but the approximations they give are close enough for everyday purposes. In Example 7.55, we rounded the number of fluid ounces to the nearest tenth.

Example 7.56

Solution

1. Choose a kilometers-to-miles factor. Use $\frac{1\ \mathrm{mile}}{1.61\ \mathrm{kilometers}}$, a factor equal to $1$ for this conversion.
2. Multiply the given distance. Compute $100\ \mathrm{kilometers}\cdot\frac{1\ \mathrm{mile}}{1.61\ \mathrm{kilometers}}$.
3. Cancel the kilometer units. The kilometers cancel, leaving $\frac{100}{1.61}$ miles.
4. Divide and round. Since $\frac{100}{1.61}=62.111\ldots$, the rest stop is about $62$ miles away to the nearest mile.

Takeaway: Using $1.61$ kilometers per mile, $100$ kilometers converts to $\frac{100}{1.61}\approx62$ miles to the nearest mile.

Convert Between Fahrenheit and Celsius Temperatures

Have you ever been in a foreign country and heard the weather forecast? If the forecast is for $22\mathrm{^{\circ}C}.$ What does that mean?

The U.S. and metric systems use different scales to measure temperature. The U.S. system uses degrees Fahrenheit, written $\mathrm{^{\circ}F}.$ The metric system uses degrees Celsius, written $\mathrm{^{\circ}C}.$ Figure 7.9 shows the relationship between the two systems.

If we know the temperature in one system, we can use a formula to convert it to the other system.

Example 7.57

Solution

1. Substitute the Fahrenheit value. Put $F=50$ into the formula to obtain $C=\frac{5}{9}(50-32)$, as the second figure shows.
2. Simplify the parentheses. Subtracting $32$ from $50$ gives $18$, so $C=\frac{5}{9}\cdot{}18$.
3. Multiply to finish. Cancel the factor $9$ with $18$ to obtain $C=5\cdot{}2=10$.
4. State the result. The temperature is $10$ degrees Celsius.

Takeaway: Subtract $32$ before multiplying by $\frac{5}{9}$ when converting Fahrenheit to Celsius.

Example 7.58

Solution

1. Substitute the Celsius value. Put $C=20$ into the formula to obtain $F=\frac{9}{5}(20)+32$, which is displayed in the second figure.
2. Multiply by $\frac{9}{5}$. Since $\frac{9}{5}\cdot{}20=9\cdot{}4=36$, the expression becomes $F=36+32$.
3. Add the constant. Adding $32$ to $36$ gives $68$.
4. State the result. The forecast temperature is $68$ degrees Fahrenheit.

Takeaway: Multiply the Celsius reading by $\frac{9}{5}$ before adding $32$ when converting to Fahrenheit.

Section 7.5 Exercises

Section 7.5 Exercises

Make Unit Conversions in the U.S. System

In the following exercises, convert the units.

Use Mixed Units of Measurement in the U.S. System

In the following exercises, solve and write your answer in mixed units.

Make Unit Conversions in the Metric System

In the following exercises, convert the units.

Use Mixed Units of Measurement in the Metric System

In the following exercises, solve and write your answer in mixed units.

Convert Between U.S. and Metric Systems

In the following exercises, make the unit conversions. Round to the nearest tenth.

Convert between Fahrenheit and Celsius

In the following exercises, convert the Fahrenheit temperature to degrees Celsius. Round to the nearest tenth.

In the following exercises, convert the Celsius temperatures to degrees Fahrenheit. Round to the nearest tenth.

Everyday Math

Writing Exercises

Self Check

ⓐ After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.

ⓑ Overall, after looking at the checklist, do you think you are well-prepared for the next chapter? Why or why not?

1. Lexie is $30$ inches tall. Convert her height to feet.

2. Rene bought a hose that is $18$ yards long. Convert the length to feet.

3. Arnold’s SUV weighs about $4.3$ tons. Convert the weight to pounds.

4. A cruise ship weighs $51,000$ tons. Convert the weight to pounds.

5. The distance between Earth and the moon is about $250,000$ miles. Convert this length to yards.

1. A team of astronauts spends $15$ weeks in space. Convert the time to minutes.

2. How many cups are in $1$ gallon?

3. How many teaspoons are in $1$ cup?

4. Laura gave birth to triplets weighing $3$ pounds $12$ ounces, $3$ pounds $3$ ounces, and $2$ pounds $9$ ounces. What was the total birth weight of the three babies?

5. Seymour cut two pieces of crown molding for his family room that were $8$ feet $7$ inches and $12$ feet $11$ inches. What was the total length of the molding?

1. Henri wants to triple his spaghetti sauce recipe, which calls for $1$ pound $8$ ounces of ground turkey. How many pounds of ground turkey will he need?

2. Joellen wants to double a solution of $5$ gallons $3$ quarts. How many gallons of solution will she have in all?

3. Sandy completed her first $\mathrm{5-km}$ race. How many meters did she run?

4. Herman bought a rug $2.5$ meters in length. How many centimeters is the length?

5. Kari’s newborn baby weighed $2800$ grams. How many kilograms did the baby weigh?

1. Anderson received a package that was marked $4500$ grams. How many kilograms did this package weigh?

2. Convert: ⓐ $\,7.25$ L to kL ⓑ $\,6.3$ L to mL.

3. Convert: ⓐ $\,350$ hL to L ⓑ $\,4.1$ L to cL.

4. Mariella is $1.58$ meters tall. Her daughter is $75$ centimeters tall. How much taller is Mariella than her daughter? Write the answer in centimeters.

5. The fence around Hank’s yard is $2$ meters high. Hank is $96$ centimeters tall. How much shorter than the fence is Hank? Write the answer in meters.

1. A recipe for Alfredo sauce calls for $250$ milliliters of milk. Renata is making pasta with Alfredo sauce for a big party and needs to multiply the recipe amounts by $8.$ How many liters of milk will she need?

2. To make one pan of baklava, Dorothea needs $400$ grams of filo pastry. If Dorothea plans to make $6$ pans of baklava, how many kilograms of filo pastry will she need?

3. How many quarts of soda are in a $\mathrm{2-liter}$ bottle?

4. How many liters are in $4$ quarts of milk?

5. The height of Mount Kilimanjaro is $5,895$ meters. Convert the height to feet. Round to the nearest foot.

1. The flight distance from New York City to London is $5,586$ kilometers. Convert the distance to miles. Round to the nearest mile.

2. Convert the Fahrenheit temperatures to degrees Celsius: $59\mathrm{^{\circ}F}.$

3. Convert the Fahrenheit temperatures to degrees Celsius: $41\mathrm{^{\circ}F}.$

4. Convert the Celsius temperatures to degrees Fahrenheit:

The temperature in Helsinki, Finland was $15\mathrm{^{\circ}C}.$

5. Convert the Celsius temperatures to degrees Fahrenheit:

The temperature in Sydney, Australia was $10\mathrm{^{\circ}C}.$

1. A floor tile is $2$ feet wide. Convert the width to inches.

2. Carson is $45$ inches tall. Convert his height to feet.

3. Faye is $4$ feet $10$ inches tall. Convert her height to inches.

4. On a baseball diamond, the distance from home plate to first base is $30$ yards. Convert the distance to feet.

5. Denver, Colorado, is $5,183$ feet above sea level. Convert the height to miles.

1. Blue whales can weigh as much as $150$ tons. Convert the weight to pounds.

2. At take-off, an airplane weighs $220,000$ pounds. Convert the weight to tons.

3. Lynn’s cruise lasted $6$ days and $18$ hours. Convert the time to hours.

4. Misty’s surgery lasted $2\frac{1}{4}$ hours. Convert the time to seconds.

5. How many tablespoons are in a gallon?

1. April’s dog, Beans, weighs $8$ pounds. Convert his weight to ounces.

2. Baby Audrey weighed $6$ pounds $15$ ounces at birth. Convert her weight to ounces.

3. Lance needs $500$ cups of water for the runners in a race. Convert the volume to gallons.

4. Judy bought $1$ pound $6$ ounces of almonds, $2$ pounds $3$ ounces of walnuts, and $8$ ounces of cashews. What was the total weight of the nuts?

5. Last year Eric went on $6$ business trips. The number of days of each was $5,2,8,12,6,\mathrm{and 3.}$ How much time (in weeks and days) did Eric spend on business trips last year?

1. Fawzi’s SUV is $6$ feet $4$ inches tall. If he puts a $\mathrm{2-foot-10-inch}$ box on top of his SUV, what is the total height of the SUV and the box?

2. Mireille needs to cut $24$ inches of ribbon for each of the $12$ girls in her dance class. How many yards of ribbon will she need altogether?

3. Kitaka hiked $8$ kilometers. Convert the length to meters.

4. The width of the wading pool is $2.45$ meters. Convert the width to centimeters.

5. The depth of the Mariana Trench is $10,911$ meters. Convert the depth to kilometers.

1. A typical ruby-throated hummingbird weights $3$ grams. Convert this to milligrams.

2. One serving of gourmet ice cream has $25$ grams of fat. Convert this to milligrams.

3. Dimitri’s daughter weighed $3.8$ kilograms at birth. Convert this to grams.

4. A bottle of medicine contained $300$ milliliters. Convert this to liters.

5. Stavros is $1.6$ meters tall. His sister is $95$ centimeters tall. How much taller, in centimeters, is Stavros than his sister?

1. Concetta had a $\mathrm{2-kilogram}$ bag of flour. She used $180$ grams of flour to make biscotti. How many kilograms of flour are left in the bag?

2. One glass of orange juice provides $560$ milligrams of potassium. Linda drinks one glass of orange juice every morning. How many grams of potassium does Linda get from her orange juice in $30$ days?

3. One serving of whole grain sandwich bread provides $6$ grams of protein. How many milligrams of protein are provided by $7$ servings of whole grain sandwich bread?

4. Frankie is $42$ inches tall. Convert his height to centimeters.

5. Connie bought $9$ yards of fabric to make drapes. Convert the fabric length to meters.

1. An average American will throw away $90,000$ pounds of trash over his or her lifetime. Convert this weight to kilograms (2.20 pounds = 1 kilogram).

2. Kathryn is $1.6$ meters tall. Convert her height to feet.

3. Jackson’s backpack weighs $15$ kilograms. Convert the weight to pounds.

4. Bernard bought $8$ gallons of paint. Convert the volume to liters.

5. $77\mathrm{^{\circ}F}$

1. $14\mathrm{^{\circ}F}$

2. $4\mathrm{^{\circ}F}$

3. $120\mathrm{^{\circ}F}$

4. $25\mathrm{^{\circ}C}$

5. $-15\mathrm{^{\circ}C}$

1. $8\mathrm{^{\circ}C}$

2. $16\mathrm{^{\circ}C}$

3. Reflectors The reflectors in each lane-marking stripe on a highway are spaced $16$ yards apart. How many reflectors are needed for a one-mile-long stretch of highway?