Activity 1.3.2 – English and Metric Linear
Measurements
Purpose
What do a driver looking down at a speedometer to make sure the car is within the
speed limit, and a chef using a tablespoon to gauge the right amount of sugar have
in common? Both are examples of measurements that occur millions of times every
day.
Modern civilization cannot exist without measurement systems. Have you ever had
to move a piece of furniture only to find out that the item would not fit through a
door? Using a tape measure to gauge the size of the door opening can save a lot of
grief. The abilities to conduct, record, and convert measurements are prerequisite
skills in the fields of science, mathematics, and engineering.
The marketplace is global. An object that is designed in the United States may end
up being manufactured in another country. The United States is the only country that
uses the English system. It is because of this global marketplace that the sizes of
engineered objects must often be communicated in both English and metric units.
Converting linear measurements to provide dual dimensioning saves the
manufacturer time, which keeps product costs down.
Equipment




Number 2 pencil
Calculator
Ruler – English to metric
Activity 1.3.2a Decimal Conversion Chart
Project Lead The Way, Inc.
Copyright 2010
IED – Unit 1 – Lesson 1.3 – Activity 1.3.2 – English and Metric Linear Measurements – Page 1
Procedure
This activity will provide you with a foundation of basic measuring skills and simple
mathematical calculations.
Complete the following questions by placing your answers in the spaces provided.
All inch measurements dealing with fractions must be answered in their lowest terms
(i.e., 4/16 in = ¼ in).
For example, if you solve a mathematical equation and the result is 4/16 in., your
answer is not in lowest terms. The lowest term answer is ¼ in. If you are unsure
why, you need to ask your teacher to explain.
Your measurement accuracy on all measurements will be to the nearest 1/16 in. You
will need to take your fractional answer and convert to decimal. All metric
measurements must be answered to the nearest millimeter.
To convert decimal inches to millimeters, multiply by 25.4.
2 in x 25.4 = 51 mm
.75 in x 25.4 = 19 mm
To convert millimeters to decimal inches, divide by 25.4
75 mm  25.4 = 2.95 in
10 mm  25.4 = .39 in
Project Lead The Way, Inc.
Copyright 2010
IED – Unit 1 – Lesson 1.3 – Activity 1.3.2 – English and Metric Linear Measurements – Page 2
Figure 1
Study Figure 1, and answer questions 1 through 8. Show all math work.
1.
Is this an English or metric scale?
2.
Distance A
Fraction:
Decimal:
Metric:
3.
Distance B
Fraction:
Decimal:
Metric:
4.
Distance C
Fraction:
Decimal:
Metric:
5.
Distance D
Fraction:
Decimal:
Metric:
6.
Distance E
Fraction:
Decimal:
Metric:
7.
What is the difference between distances A and C?
Fraction:
8.
Decimal:
Metric:
What is the difference between distances B and E?
Fraction:
Decimal:
Metric:
Project Lead The Way, Inc.
Copyright 2010
IED – Unit 1 – Lesson 1.3 – Activity 1.3.2 – English and Metric Linear Measurements – Page 3
Figure 2
Study Figure 2, and answer questions 9 through 16. Show all math work.
9.
Is this an English or metric scale?
10.
Distance A
Metric:
Decimal:
Fraction:
11.
Distance B
Metric:
Decimal:
Fraction:
12.
Distance C
Metric:
Decimal:
Fraction:
13.
Distance D
Metric:
Decimal:
Fraction:
14.
Distance E
Metric:
Decimal:
Fraction:
15.
What is the difference between distances A and C?
Metric:
16.
Decimal:
Fraction:
What is the difference between distances B and E?
Metric:
Decimal:
Fraction:
Project Lead The Way, Inc.
Copyright 2010
IED – Unit 1 – Lesson 1.3 – Activity 1.3.2 - English and Metric Linear Measurements – Page 4
17. Figure 3 shows a design of a mounting bracket for a dishwasher valve. This
mechanical part, which was designed in the United States, is being out-sourced to a
country using the metric system for manufacturing. Convert the inch dimensions to
millimeters, and write your answer within the brackets.
Figure 3
18. Optional: Figure 4 is a gasket for a go-cart engine. The drawing was created in
a country using the metric system for manufacturing. The part is being mass
produced in the United States. Convert the millimeter dimensions to inches so the
part can be created. Write your answers in the brackets provided.
Project Lead The Way, Inc.
Copyright 2010
IED – Unit 1 – Lesson 1.3 – Activity 1.3.2 - English and Metric Linear Measurements – Page 5
Figure 4
Conclusion
1. Why is the metric system used instead of the English system, and vice versa, in
various parts of the world?
2. When you look at a drawing, how do you know if you are looking at inch or
millimeter values? Why is it important for an engineer to know this piece of
information?
3. Why would you have to know how to convert measurements when looking at
working drawing?
Project Lead The Way, Inc.
Copyright 2010
IED – Unit 1 – Lesson 1.3 – Activity 1.3.2 - English and Metric Linear Measurements – Page 6