Geometry: 3D to 2D and Back Again

1
Concrete Representations of Geometric Concepts
National Council of Teachers of Mathematics 2007
Annual Meeting and Exposition Atlanta, Georgia
-- March 22, 2007
Dr. Nancy F. Matthews Montgomery Central Middle
School -- Cunningham, TN nancy.matthews_at_cmcss.net
Kay D. Haralson Austin Peay State University --
Clarksville, TN haralsonk_at_apsu.edu
2
Do These Nets form Cubes? For each net,
write your prediction on the net. Cut out the
net and fold. Did it make a cube? Were your
predictions correct? Sort the nets into cubes
and not cubes. Write a generalization for
predicting which nets make cubes.
3
Test your generalization on the following
nets. Predict, then cut and fold.
4
Do These Nets form Triangular
Prisms? For each net, write your prediction on
the net. Cut out the net and fold. Did it
make a Triangular Prism? Were your predictions
correct? Sort the nets into Triangular Prisms
and not Triangular Prisms. Write a
generalization for predicting which nets make
Triangular Prisms.
5
Do These Nets form Prisms? For each
net, write your prediction on the net. Cut
out the net and fold. Did it make a Triangular
Prism? Were your predictions correct? Sort
the nets into Prisms and not Prisms. Write a
generalization for predicting which nets make
Prisms.
6
Do These Nets form Pyramids? For each
net, write your prediction on the net. Cut out
the net and fold. Did it make a pyramid? Were
your predictions correct? Sort the nets into
pyramids and not pyramids. Write a
generalization for predicting which nets make
pyramids.
7
1. The net below is folded to form a cube.2.
Predict how the other 2 sides be labeled when
placed as shown?3. Be sure the letters are in
the correct orientation.4. Cut the net and fold
to form a cube. 5. Were your predictions
correct?