Let’s go to the ballet

0See if you can accurately name all the shapes

Polyhedrons Polyhedrons

Pyramids PrismsPyramids Prisms

Lesson Objectives

0To understand the differences between platonic solids, prisms and pyramids

0To examine the properties of polyhedrons0To develop your own NET shapes using 3D shapes

provided

Polyhedrons

0Poly = Greek for many0Hedron = Greek for face

0Polyhedron = Many Faces!!

Likely Difficulties

0Names for 2D figures and 3D objects often get confused because the beginning of names are similar…

0Dodecagon = 12 sided 2D shape0Dodecahedron = 3D 12 sided regular pentagon

3D Shape Properties

Platonic Polyhedrons

0 Plato, a Greek philosopher and mathematician.

0Worked out that some polyhedrons are identical in shape and size.

0Edges = Same length0Angles = Same size0 Vertices = Identical

What does that mean?

Platonic Polyhedrons are Perfect!

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

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

Pyramids & Prisms0Prisms have two identical, parallel faces joined to one

another by rectangles. Examples are;

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

Other 3D shapes

Activity!

0You will be given some examples of 3D shapes0Name the shapes you have been given0With your elbow partner, use the graph paper

provided to draw a NET of the shapes you have been given

0Cut 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)

0Did you get it right? If not, what do you need to change to make it correct?