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
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