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Lesson 1.3 Check Your Understanding
Master 1.13
1. A Canadian football field is approximately 59 m wide.
What is this measurement to the nearest foot?
Solution
1
4
From the table, 1 m 3 ft.
( )
59 m 59 ( ft.)
1
4
So, 59 m 59 3 ft.
13
4
59 m 767
4
ft.
3
4
59 m 191 ft.
A width of 59 m is approximately 192 ft.
2. After meeting in Osoyoos, B.C., Takoda drove 114 km north and Winona drove
68 mi. south. Who drove farther?
Solutions
To compare the distances, convert one measurement so the units are the same.
Method 1
Convert the distance Winona drove from miles to kilometres.
1 mi. 1.6 km
So, 68 mi. 68(1.6 km)
68 mi. 108.8 km
Since 108.8 km < 114 km, Takoda drove farther.
Method 2
Convert the distance Takoda drove from kilometres to miles.
1 km 6
10
mi.
So, 114 km 114
114 km 68
Since 68
2
5
(
6
10
4
10
mi.
)
mi., or 68
2
5
mi.
> 68, Takoda drove farther.
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Lesson 1.3 Check Your Understanding
Master 1.13
3. Nora knows that she is 5 ft. 7 in. tall.
a) What height in centimetres will she list on her driver’s license application?
b) Use mental math and estimation to justify that the answer is reasonable.
Solution
a) Convert 5 ft. 7 in. to inches.
1 ft. = 12 in.
So, 5 ft. = 5(12 in.)
5 ft. = 60 in.
And, 5 ft. 7 in. = 60 in. + 7 in.
5 ft. 7 in. = 67 in.
Write a proportion to convert 67 in. to centimetres.
Let h represent Nora’s height in centimetres.
The ratio of h centimetres to 67 in. is approximately equal to
the ratio of 1 cm to
Write
4
10
4
10
in.
as 0.4.
h
1
67
0.4
67 
Multiply each side by 67.
h 
 67
 
67 
1 

0.4


h 67
0.4
h 167.5
Nora will list her height as 168 cm.
b) To check:
1 ft. 30 cm
5 ft. 5(30 cm)
5 ft. 150 cm
6 ft. 6(30 cm)
6 ft. 180 cm
5 ft. 7 in. is approximately half way between 5 ft. and 6 ft.
168 cm is approximately half way between 150 cm and 180 cm.
So, 5 ft. 7 in. 168 cm is reasonable.
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This page may have been modified from its original. Copyright © 2010 Pearson Canada Inc.
6
Master 1.13
Lesson 1.3 Check Your Understanding
4. A truck driver knows that his load is 15 ft. wide. Regulations along his route
state that any load over 4.3 m wide must have wide-load markers and
an escort with flashing lights. Does this vehicle need wide-load markers?
Justify your answer.
Solution
Write a proportion to convert 15 ft. to metres.
Let w represent the width of the vehicle in metres.
The ratio of w metres to 15 ft. is approximately equal to the ratio of 0.3 m to 1 ft.
w
0.3
15
1
15 
w
 15
 
Multiply each side by 15.
15 
0.3 

 1 
w 4.5
The vehicle is approximately 4.5 m wide, so it needs wide-load markers.
The width is an estimate that is very close to the regulation width.
To be sure wide-load markers are needed, calculate an exact conversion.
Convert the width of the vehicle in inches to centimetres.
Use the conversion:
2.54 cm = 1 in.
First write the width of the vehicle in inches.
15 ft. = 15(12) in.
15 ft. = 180 in.
So,
180 in. = 180(2.54) cm
180 in. = 457.2 cm
180 in. =
457.2
100
Convert centimetres to metres.
m
180 in. = 4.572 m
The vehicle is approximately 4.6 m wide.
This measure is a little more than 4.3 m, so the vehicle needs wide-load markers.
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This page may have been modified from its original. Copyright © 2010 Pearson Canada Inc.
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