Geometric Constructions
During this lesson, you will duplicate
segments and angles using your
straightedge & compass.
INTRODUCTION
During this week, you will learn how to
perform basic geometric constructions,
using your straightedge and compass. As
you work with your team members,
remember to share the tasks and compare
results. You should keep a record of your
investigations and a separate list of your
conjectures in your notebook.
A Few Words on Geometric
Constructions…
“Geometric figures created
with a compass and
straightedge only are called
____________________.
geometric constructions
Since the Golden Age of
Greece, people have made a
game of geometric
constructions. Over the
centuries, people have enjoyed
using their construction tools
to discover geometry.”
Discovering Geometry, KEY CURRICULUM PRESS,
Serra, 1993
Construction Tips
1. Read the “Construction Tips” provided to you in your
notes packet.
2. Create a “brainstorming” list of key ideas.
Comparison: Sketching, Drawing, and
Constructing
Method
Construct
Draw
Sketch
Tools
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Construction:
Construction:
Construction:
Segments
Construction:
Construction:
Construction:
Construction:
Duplicating a Line Segment
Sum of Two Segments
Difference of Two
Equilateral Triangle
Regular Quadrilateral
Duplicating an Angle
Sum of Two Angles
Final Check for Understanding
_______________
A
B
__________
C
___
D
E
F
1. Duplicate, by construction, the line
segments above.
2. Use your copies of the segments above to
construct the following:
a. AB + EF
b. 2AB - CD