Solids: Three –Dimensional figures

Solids: Three –Dimensional

figuresEQ: How do you identify

various three-dimensional figures?

What are three-dimensional figures?

• A three-dimensional figure encloses a part of space.

• In other words it can hold something (water, air, etc.)

What is a Polyhedron?

A 3-dimensional figure that has polygons as faces

Polygons must have straight lines!

Polyhedrons Not Polyhedrons

Features of a 3-D figure

Faces

EdgeVertex

• Edge- formed by two faces of a 3-D figure sharing a side

• Vertex (plural:vertices)- the point at which three or more edges meet

•Face- the flat surface of a figure

Identify the number of faces, edges, and vertices on each three-dimensional figure.

A.

B.

5 faces8 edges5 vertices

7 faces15 edges10 vertices

Faces + Vertices -2 = Edges

Identify the number of faces, edges, and vertices on each three-dimensional figure.

A.

B.

6 faces12 edges8 vertices

5 faces9 edges6 vertices

Two main types of 3-D Figures

• Prism:– Has at least three

faces that are rectangles

– Has two congruent faces on the top and bottom called bases

– The shape of the base tells what type of prism the figure is

• Pyramid:– Has at least three

faces that are triangles

– Has only one base

– The shape of the base tells what type of pyramid the figure is

Prisms

Rectangular Prism

Pentagonal Prism

Pyramids

Square Pyramid

Triangular Pyramid

Other 3-D Figures

• Cone- is a figure like a pyramid, but has a circular base and a curved surface

Other 3-D Figures

• Cylinder- a curved figure with two circular bases

Other 3-D Figures

• Sphere- a 3-D figure with no faces, bases, edges, or vertices

Cylinder

Triangular Prism

Cube

Square Pyramid

Okay…this last one is hard…Ready??

Pentagonal Pyramid

What is a net?

A net is a two-dimensional (flat) representation of a three-dimensional object. A net would be what your cereal box becomes when you slice down a few sides.

Identify what shape will be made from the following nets.1. 2.

ANSWERS

A net is a two-dimensional (flat) representation of a three-dimensional object. A net would be what your cereal box becomes when you slice down a few sides.

Identify what shape will be made from the following nets.1. Triangular Pyramid 2. Cube

NetsIdentify what shape will be made from

the following nets. A net is a two-dimensional (flat) representation of a

three-dimensional object. A net would be what your cereal box becomes when you slice down a few sides.

Identify what shape will be made from the following nets.

1. 2. 3. 4.

ANSWERS

A net is a two-dimensional (flat) representation of a three-dimensional object. A net would be what your cereal box becomes when you slice down a few sides.

Identify what shape will be made from the following nets.

1. 2. 3. 3. 4.

cylinder square pyramid cone triangular prism

Identify what shape will be made from the following nets.

1. 2. 3.

Identify what shape will be made from the following nets.

1. 2. 3. rectangular prism cylinder triangular prism

Cube or Not?

http://illuminations.nctm.org/Activity.aspx?id=3544

Summary

How are 3D shapes classified?

What is a net?