This document introduces geometric constructions using a straightedge and compass. It defines key terms like straightedge, compass, and construction. The objectives are for students to be able to make basic constructions to copy segments and angles, bisect segments and angles, and construct perpendicular lines. Links are provided for online instructions on various geometric constructions.

1. 1-7 Constructions
Chapter 1 Tools of Geometry
©Tentinger

2. Essential Understanding and
Objectives
 Essential Understanding: You can use special
geometric tools to make a figure that is congruent
to an original figure without measuring. This
method is more accurate than sketching and
drawing
 Objectives
 Students will be able to
 Make basic constructions using a straightedge and
a compass

3. Iowa Core Curriculum
 Geometry:
 G.CO.12 Make formal geometric constructions
with a variety of tools and methods (compass and
straightedge, string, reflective devices, paper
folding, dynamic geometric software, etc.).
Copying a segment; copying an angle; bisecting a
segment; bisecting an angle; constructing
perpendicular lines, including the perpendicular
bisector of a line segment; and constructing a line
parallel to a given line through a point not on the
line.

4. Definitions
 Straightedge: a ruler with no markings on it
 Compass: geometric tool used to draw circles and
parts of circles called arcs
 Construction: geometric figure drawn using a
straightedge and a compass.

5. Making Constructions
 Home Page:
http://www.mathopenref.com/tocs/constructionsto
c.html
 Congruent Segments:
http://www.mathopenref.com/constcopysegment.
html
 Congruent Angles
 http://www.mathopenref.com/constcopyangle.html

6. More Terms
 Perpendicular Lines: two lines that intersect to
form a right angle
 Perpendicular Bisector: a line, segment, or ray
that is perpendicular to the segment at its
midpoint
 Angle Bisector: a line, segment, or ray that splits
an angle into two congruent parts

7. More Constructions
 Perpendicular Bisector:
http://www.mathopenref.com/constbisectline.html
 Angle Bisector:
http://www.mathopenref.com/constbisectangle.ht
ml

8. Homework
 Worksheet – In class