Skip to content Skip to navigation

OpenStax-CNX

You are here: Home » Content » Three dimensional objects

Navigation

Lenses

What is a lens?

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

This content is ...

In these lenses

  • GETSenPhaseMaths display tagshide tags

    This module is included inLens: Siyavula: Mathematics (Gr. 7-9)
    By: Siyavula

    Review Status: In Review

    Click the "GETSenPhaseMaths" link to see all content selected in this lens.

    Click the tag icon tag icon to display tags associated with this content.

Recently Viewed

This feature requires Javascript to be enabled.

Tags

(What is a tag?)

These tags come from the endorsement, affiliation, and other lenses that include this content.
 

Three dimensional objects

Module by: Siyavula Uploaders. E-mail the author

MATHEMATICS

Perimeter, Area and Volume

EDUCATOR SECTION

Memorandum

20.3.2

a) sphere

pyramid

cube

cylinder

triangular prism

cone

hexagonal prism

c) b) 8; 12; 6

c) 5; 8; 5

d) 6; 10; 6

e) 12; 18; 8

f) 6; 9; 5

d) a) right-angled or rectangular prism

b) cube

c) pyramid

d) pentagonal pyramid

e) hexagonal prism

LEANER SECTION

Content

ACTIVITY: Three dimensional objects [LO 3.1, LO 3.2]

20. THREE DIMENSIONAL OBJECTS

20.1 Did you know?

Two-dimensional objects have only two dimensions, namely length and breadth, that enable us to calculate perimeter and area.

Three-dimensional objects have three dimensions: length, breadth and height, which enable us to calculate volume.

20.2 Did you also know?

Figure 1
Figure 1 (graphics1.png)

20.3 Let us look at a few dimensional objects:

20.3.1 Interesting to know!

Three-dimensional figures are also known as cubic figures. Some figures have four or more faces (see sketch above) and are called polyhedrons.

The word polyhedron is Greek, which means many edges. The first polyhedrons were discovered more than 2 000 years ago by a Greek Mathematician, Euclid.

20.3.2 Work with a friend

a) Match each form with the correct description:

Table 1
graphics2.png   pyramid
graphics3.png   hexagonal prism
graphics4.png   sphere
graphics5.png   cone
graphics6.png   triangular prism
graphics7.png   cube
graphics8.png   cylinder

b) Now use the above information and group the following items. Then report back to the class, providing reasons why you have grouped the forms in this way.

Figure 2
Figure 2 (graphics9.png)

c) Complete the following table:

Table 2
  Figure Vertex Edge Face
e.g.a) graphics10.png 8 12 6
b) graphics11.png __________ __________ __________
c) graphics12.png __________ __________ __________
d) graphics13.png __________ __________ __________
e) graphics14.png __________ __________ __________
f) graphics15.png __________ __________ __________

d) Can you name all the figures above?

a) _______________________________________________________________

b) _______________________________________________________________

c) _______________________________________________________________

d) _______________________________________________________________

e) _______________________________________________________________

f) _______________________________________________________________

21. Let us take a closer look at three-dimensional objects.

21.1.1 Did you know?

A cube is a square shape. Thus all its edges are equally long.

21.1.2 Look at this cube.

Can you draw this cube from another angle?

Figure 3
Figure 3 (graphics16.png)

Assessment

Learning Outcome 3:The learner will be able to describe and represent characteristics and relationships between two-dimensional shapes and three-dimensional objects in a variety of orientations and positions.

Assessment Standard 3.1:We know this when the learner recognises visualises and names geometric figures and solids in natural and cultural forms and geometric settings, including those previously dealt with;

Assessment Standard 3.2:We know this when the learner in contexts that include those that may be used to build awareness of social, cultural and environmental issues, describes and classifies geometric figures and solids in terms of properties.

Content actions

Download module as:

Add module to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

| A lens I own (?)

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks