An overview of the properties of polyhedrons, prisms and pyramids

1. Let’s go to the ballet
0 See if you can accurately name all the shapes

2. Polyhedrons
Polyhedrons
Pyramids Prisms
Pyramids Prisms

3. Lesson Objectives
0 To understand the differences between platonic
solids, prisms and pyramids
0 To examine the properties of polyhedrons
0 To develop your own NET shapes using 3D shapes
provided

4. Polyhedrons
0 Poly = Greek for many
0 Hedron = Greek for face
0 Polyhedron = Many Faces!!

5. Likely Difficulties
0 Names for 2D figures and 3D objects often get
confused because the beginning of names are
similar…
0 Dodecagon = 12 sided 2D shape
0 Dodecahedron = 3D 12 sided regular pentagon

6. 3D Shape Properties

7. Platonic Polyhedrons
0 Plato, a Greek philosopher and
mathematician.
0 Worked out that some polyhedrons are identical in
shape and size.
0 Edges = Same length
0 Angles = Same size
0 Vertices = Identical

8. What does that mean?

9. Platonic Polyhedrons are
Perfect!
0 All vertices are surrounded by the same plane shape.
0 Any face can be the base.
0 They are beautifully symmetrical.
0 Only five of them exist!

10. Platonic
Solid
Picture
Number
of Faces
Shape of
Faces
Number
of Faces
at Each
Vertex
Number
of
Vertices
Number
of Edges
Unfolded
Polyhedron (Net)
Tetrahedron 4
Equilateral
Triangle
(3-sided)
3 4 6
Cube 6
Square
(4-sided)
3 8 12
Octahedron 8
Equilateral
Triangle
(3-sided)
4 6 12
Dodecahedron 12
Regular
Pentagon
(5-sided)
3 20 30
Icosahedron 20
Equilateral
Triangle
(3-sided)
5 12 30

11. Pyramids & Prisms
0 Prisms have two identical, parallel faces joined to one
another by rectangles. Examples are;

12. Pyramids & Prisms
0 Pyramids have one face with at least 3 edges, the faces
meeting these edges are ALL triangles.
0 NOTE: Pyramids get their name from the shape of their
base
0 There are many more pyramids than these ones shown

13. Other 3D shapes

14. Activity!
0 You will be given some examples of 3D shapes
0 Name the shapes you have been given
0 With your elbow partner, use the graph paper
provided to draw a NET of the shapes you have been
given
0 Cut out the Nets you have drawn and see if they can
be made into the original 3D shapes (you might want
to leave a lip on some sides so you can glue it
together)
0 Did you get it right? If not, what do you need to
change to make it correct?