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| 14 Theory slides |
| 10 Exercises - Grade E - A |
| Each lesson is meant to take 1-2 classroom sessions |
Two student-led teams, one from Canada and the other the US, made remote controlled robotic cars. Ignacio, of the US, controls the his team's car — Hyperion. Emily, of Canada, controls her team's car — Photon. They are both participating in an international competition and are now doing a test run at the competition site.
Ignacio races the robotic car as fast as he can through classrooms, the mountain, around the lake, and finally finishes at the Theatre. Emily's follows a similar path but spends more time going through the mountains. How cool!
Ignacio's robotic car, Hyperion, traveled 0.4 miles in 2 hours. Emily's robotic car, Photon, traveled at an average speed of 0.4 kilometers per hour. Which robotic car drove at a higher average speed?
Fact | 1 foot is equal to 12 inches. | 1 hour is equal to 60 minutes. |
---|---|---|
Ratio | 12 in.1 ft | 60 min1 h |
Write the given ratio in the indicated form.
Write a ratio using the fact that 1 inch on the map represents 0.075 miles in real distance.
a⋅cb=ca⋅b
Cross out common units
Cancel out common units
Multiply
1a=a
Given Quantity | Conversion | Result |
---|---|---|
2 hours | 2 hours⋅1 hour60 minutes | 120 minutes |
Although the final result is in minutes, both quantities represent the same amount of time. Note that the opposite conversion, from minutes to hours, has a conversion factor of 60 minutes1 hour. If the task was to convert 120 minutes to hours, 120 minutes would be multiplied by this conversion factor.
Given Quantity | Conversion | Result |
---|---|---|
120 hours | 120 minutes⋅60 minutes1 hour | 2 hours |
As shown in the examples above, the process of including units of measurement as factors is called dimensional analysis. Dimensional analysis can also be used when deciding which conversion factor will produce the desired units. In the table, some common conversion factors are used to convert the given measures.
Given Quantity | Conversion | Result |
---|---|---|
3 pounds | 3 pounds⋅1 pound16 ounces | 48 ounces |
160 ounces | 160 ounces⋅16 ounces1 pound | 10 pounds |
1 mile | 1 mile⋅1 mile1760 yards | 1760 yards |
Some common conversions involve distance, mass, area, volume, time, and temperature.
The numerator and denominator of the conversion factor represent the same quantity. That means their quotient equals 1. Then, by the Identity Property of Multiplication, the amount of the given quantity does not change when multiplied by the conversion factor.
When converting from one unit to another, the desired unit needs to be in the numerator of the conversion factor while the given unit needs to be in the denominator. That way when the quantity is multiplied by the conversion factor, the given unit will cancel out and the desired unit will remain.
Keep in mind that, despite the given quantity and the new quantity have different values, they represent the same amount.
Customary Units | ||
---|---|---|
Type | Unit | Equivalent Unit |
Length | 1 foot (ft) | 12 inches (in.) |
1 yard (yd) | 3 feet | |
1 mile (mi) | 5280 feet | |
Weight | 1 pound (lb) | 16 ounces (oz) |
1 ton (T) | 2000 pounds | |
Volume | 1 cup (c) | 8 fluid ounces (fl oz) |
1 pint (pt) | 2 cups | |
1 quart (qt) | 2 pints | |
1 gallon (gal) | 4 quarts |
The robotics competition that each team will join requires that the robotic cars weigh less than 6 pounds. The robotic car designed by Ignacio's team, Hyperion, currently weighs 84 ounces.
a⋅cb=ca⋅b
Cross out common units
Cancel out common units
a⋅1=a
ca⋅b=ca⋅b
Calculate quotient
The table shows the commonly used metric units of length.
Unit | Equivalent Unit |
---|---|
1000 millimeters (mm) | 1 meter (m) |
100 centimeters (cm) | 1 meter |
10 decimeters (dm) | 1 meter |
1 dekameter (dam) | 10 meters |
1 hectometer (hm) | 100 meters |
1 kilometer (km) | 1000 meters |
For measuring capacity, the metric system uses the liter as the base unit.
Unit | Equivalent Unit |
---|---|
1000 milliliters (mL) | 1 liter (L) |
100 centiliters (cL) | 1 liter |
10 deciliters (dL) | 1 liter |
1 dekaliter (daL) | 10 liters |
1 hectoliter (hL) | 100 liters |
1 kiloliter (kL) | 1000 liters |
In the metric system, kilogram, gram, and milligram are some commonly used units for measuring weight.
Unit | Equivalent Unit |
---|---|
1000 milligrams (mg) | 1 gram (g) |
100 centigrams (cg) | 1 gram |
10 decigrams (dg) | 1 gram |
1 dekagram (dag) | 10 grams |
1 hectogram (hg) | 100 grams |
1 kilogram (kg) | 1000 grams |
Ignacio's team discovered that their robotic car met the weight criteria. At the same time, Emily's team was putting another criterion to the test. The length criterion requires that the cars are no longer than 40 centimeters.
a⋅cb=ca⋅b
Cross out common units
Cancel out common units
1a=a
Multiply
Units in the customary system can be converted to units in the metric system and vice versa. This may necessitate recalling a lengthy list of conversion factors.
Emily and Ignacio are filling out the application form for the robotics competition. They must enter the measurements of their cars in multiple system's units.
Applications | ||||
---|---|---|---|---|
Name of Robotic Car | Weight | Length | ||
Hyperion | 5.25 pounds | A kilograms | 15 inches | B centimeters |
Photon | C pounds | 2.5 kilograms | D inches | 35 centimeters |
Remember, 1 kilogram is about 2.2 pounds and 1 inch is 2.54 centimeters.
Notice that Hyperion's known measurements are in customary units, whereas Photon's known measurements are in metric units. Conversion between the systems is needed. The equivalent weights will be found first followed by the equivalent lengths.
a⋅cb=ca⋅b
Cross out common units
Cancel out common units
a⋅1=a
ca⋅b=ca⋅b
Calculate quotient
Round to 2 decimal place(s)
a⋅cb=ca⋅b
Cross out common units
Cancel out common units
1a=a
Multiply
a⋅cb=ca⋅b
Cross out common units
Cancel out common units
1a=a
Multiply
a⋅cb=ca⋅b
Cross out common units
Cancel out common units
a⋅1=a
ca⋅b=ca⋅b
Calculate quotient
Round to 2 decimal place(s)
The robotics competition has finally come. Each team will race on an 80-foot track. Opposing teams are watching live from their computers.
The live camera is not that good. The students watching decide to do some math to get a better idea of who is winning!
Equivalent Quantities | Conversion Factor |
---|---|
1 ft=12 in. | 1 ft12 in. |
1 min=60 sec | 60 sec1 min |
Multiply fractions
Cross out common units
Cancel out common units
a⋅1=a
Multiply
Calculate quotient
Equivalent Quantities | Conversion Factor |
---|---|
1 ft=30.48 cm | 1 ft30.48 cm |
1 min=60 sec | 60 sec1 min |
Multiply fractions
Cross out common units
Cancel out common units
a⋅1=a
Multiply
Calculate quotient
Hyperion | Photon | |
---|---|---|
Speed=TimeDistance | 5 min80 ft | 16 min240 ft |
Simplify | 16minft | 15minft |
As can be seen, Hyperion can travel 16 feet in a second whereas Photon can travel 15 feet per second. Therefore, Hyperion is faster. Alternatively, the answers found in Part A and Part B can be used. However, a conversion between inches and centimeters is required here.
Hyperion | Photon | |
---|---|---|
Speed | 3.2secin. | 7.62seccm |
Now take another look at this lesson's challenge comparing the average speeds of two robotic cars. This problem can be completed with the gained knowledge of converting different measurements. Make a table using the given information.
Given | |
---|---|
Hyperion (Ignacio's) | 0.4 miles in 2 hours |
Photon (Emily's) | 0.4 kilometers per hour |
Multiply fractions
Cross out common units
Cancel out common units
a⋅1=a
ba=b/1.6a/1.6
Round to 1 decimal place(s)
Convert each measure to the indicated unit of measure.
Let's take a look at the given statement. 64 fl oz = c The units in the statement are the units used by the customary system. The symbol c stands for cups and fl oz stands for fluid ounces. We know that 1 cup is equal to 8 fluid ounces. 1c = 8fl oz Converting between cups and fluid ounces involves using a conversion factor. We will use the conversion factor 1c8 fl oz. Multiplying with this factor will eliminate the unit that appears in the given quantity. 1c/8fl oz Let's multiply 64 fl oz and the conversion factor.
We need to write 8 into the blank space. 64 fl oz = 8 c
We want to convert from tons (T) to pounds (lb).
7/20 T = lb
Remember that 1 ton is equal to 2000 pounds.
1T = 2000lb
We will use the conversion factor 2000lb1 T to convert between tons and pounds. Multiplying the given measure by this factor will result in pounds.
Therefore, the given measure is equal to 700 pounds. 7/20 T = 700 lb
Convert each measure to the indicated unit of measure.
Let's take a look at the given statement. 3.4 L = cL The letter L stands for liters. The liter is the base unit of capacity measurement in the metric system. We also know that 1 liter is equal to 100 centiliters. 1L = 100cL We want to convert from liters to centiliters. The appropriate conversion factor in this case will be 100cL1 L. Multiplying by this factor will leave us the unit we need. 3.4 L * 100cL/1 L Let's perform the multiplication.
We can fill in the blank with 100. 3.4 L = 340 cL
In this case, we are asked to convert from grams (g) to kilograms (kg).
10 000 g = kg
We will use the fact that 1 kilogram is equal to 1000 grams.
1kg = 1000g
We will use the conversion factor 1kg1000 g. This factor will allow us to cancel out the common unit when we multiply the given weight by it.
10 000 g * 1kg/1000 g
Let's perform the multiplication.
This means that 10 000 grams is equivalent to 10 kilograms. 10 000g = 10 kg
Convert each measure to the indicated unit of measure. Round the answer to two decimal places.
We want to convert between miles (mi) and kilometers (km). 22 mi ≈ km We will use a conversion factor to do so. Recall that 1 mile is about 1.61 kilometers. The appropriate conversion factor in the given case is 1.61km1 mi. 1mi ≈ 1.61km ⇓ 1.61km/1 mi Multiplying 22 miles by this conversion factor will convert it to kilometers.
We can fill in the blank with 35.42. 22 mi ≈ 35.42 km
We are asked to convert from kilograms (kg) to ounces (oz).
35 kg ≈ oz
We will use the fact that 1 kilogram is about 35.27 ounces. The conversion factor 35.27oz1 kg will allow us to cancel out the common unit.
1 kg ≈ 35.27 oz
⇓
35.27oz/1 kg
Let's multiply 35 kg by the conversion factor.
This means that 35 kilograms are about 1234.45 ounces. 35kg ≈ 1234.45 oz
Fill in each square with >, =, or < to make a true statement.
We want to compare the given values by writing a sign <, >, or = between them. First, take a look at the units in the given statement. 3 12 yd 10 12 ft Both yards (yd) and feet (ft) are customary units of length. We need to convert one of them to the other unit to compare these values. Recall how yards and feet are related. 1 yd = 3 ft We will write a conversion factor using this equation. Let's convert 3 12 yards to feet. Since we want to convert yards to feet, our ratio will have yards in the denominator. We need to write 3 feet in the numerator and 1 yard in the denominator. Conversion Factor 3ft/1yd Let's multiply 3 12 yards and the conversion factor. We will start with writing the mixed number as improper fraction. Then, we will divide out the common units. This will give us the desired unit, feet.
We can rewrite the fraction as a mixed number.
We obtained the value on the other side of the box. Therefore, 3 12 yards is equal to 10 12 feet. Knowing that we can fill in the blank. 3 12 yd = 10 12 ft
In this case, we need to compare two quantities measured in different systems. The gallon (gal) is a customary unit, and the liter (L) is a metric unit. Both are used to measure capacity or volume.
26 gal 100 L
We need to convert one of them to the other unit to compare these values. Recall the relationships between these units.
1 gal ≈ 3.79 L
Let's convert 26 gal to liters. We need to write an appropriate conversion factor to do so. Since we want to convert gallons to liters, we write 3.79L in the numerator and 1 gal in the denominator.
3.79L/1gal
Let's multiply 26 gal and the conversion factor.
This is less than 100 L. We can fill in the square with <. 26 gal < 100 L ⇕ 98.54 L < 100 L
We want to convert 12 yards per second to yards per minute. Let's first write 12 yards per second as a fraction. 12 yards per second ⇒ 12 yd/1 sec We will use a conversion factor between seconds and minutes. We know that 1 minute is 60 seconds. Our conversion factor will have minutes in the denominator because we want to convert per second to per minute. Conversion Factor 60sec/1min We can now multiply 12 yards per second by the conversion factor.
We have found that 12 yards per second is 720 yards per minute.
Let's start by writing 342 liters per hour as a fraction.
342 liters per hour ⇒ 342 L/1 h
We want to convert liters per hour to liters per minute. This requires the use of a conversion factor between minutes and hours. Let's recall that 1 hour is 60 minutes. The conversion factor will have minutes in the denominator so that minutes can cancel out.
Conversion Factor
1h/60min
Now let's multiply 342 liters per hour by this conversion factor.
Therefore, 342 liters per hour is 5.7 liters per minute.