MATHEMATICS TOPIC: Properties of Geometric shapes (2D’s and 3 D’s) (Lesson 4) STRAND:GEOMETRY

FOCUS QUESTION

How are the characteristics of geometric solids similar and different?

SPECIFIC OBJS.

1.  Draw and describe nets of prisms

2.  Identify and create solids that are polyhedral (tetrahedron, hexahedron and octahedron)

3.Classify solid shapes (prisms, pyramids and polyhedron) according to their properties.

CONTENT SUMMARY

Solids have faces, edges and vertices.  The faces are the flat surfaces of solids. The edges are the places where two faces meet. The vertices are the corners. Singular vertex, plural vertices.

Solids are three-dimensional shapes.   A prism is a solid, with two parallel faces called bases. The other faces are always parallelograms. The prism is named by the shape of its base.  A solid is a pyramid if it has 3 or more triangular faces sharing a common vertex. The base of a pyramid may be any polygon.   An edge is formed where two faces meet.   A vertex is the point where three or more faces meet. 

3-D means three dimensional (length, breath, depth). They can be regular or irregular.

A polyhedron is a 3-D solid with flat faces and straight edges or polygonal faces. Some examples include prisms and pyramids. Cylinder and cone are not polyhedrons or polyhedral. This is so because their faces are not all polygons.

Singular polyhedron-  Plural polyhedral

Polyhedron can be considered regular or irregular. For  them to be regular, all their faces must be equal /congruent example the cube. ( It has six equal faces and is called a hexahedron) The triangular pyramid is also a polyhedron as  it has four equal/congruent faces. (It is called a tetrahedron). Examples of irregular polyhedron are rectangular prism. (all the faces are not the same, neither are they congruent).

ENGAGE

Students will review what nets are and complete an oral exercise by identifying the solids that the nets shown represent and vice versa.

Tell what they think a polyhedron is. In groups they will try to find a working definition for same.

EXPLORE

Let us read this chart below. What is your understanding of it.

Take a look at this video clip.

Video Clip: What it a  polyhedron?

EXPLAIN

Tell what polyhedra are and provide examples of polyhedra.

Explain to Tim which of the solids below are polyhedra and which aren't and why.

EXTEND/ELABORATE

Students will complete the table below in groups. Make a [ü]  for columns 3 and 4.

 

SOLIDS	Name	Example of Polyhedron	Not a Polyhedron	Justification
	Cube
	Square  based pyramid
	Sphere
	Triangular prism
	Triangular pyramid
	Cylinder

EVALUATE

1. Complete the quiz below

  Quiz

2. Explain how the solids below are similar and how they are different.

Solids	Same	Different
cone, cylinder
Cube,         cuboid
Cube,      square-base prism
Square base prism,  sphere

           3.  Use the words below to complete the short paragraph.

                             congruent    polygonal    irregular     equal     faces   dimension

A polyhedron is a solid with flat ______________ and straight edges. All the faces of a polyhedron are______________. Polyhedra with all faces equal or ___________ are called regular polyhedra. __________ polyhedra have faces that are not __________ or congruent.

 

 4.  Classify the solids below as regular or irregular, polyhedra or not a polyhedron

                      

 

 

Regular Polyhedron	Irregular Polyhedron	Not a Polyhedron

 5.       Read the statements below and indicate with a [ü] if each is TRUE or FALSE

STATEMENTS	TRUE	FALSE
A polyhedron can be a prism as well as a pyramid
For a solid to be considered as a polyhedron, then all the faces must be a polygon
A sphere is a polyhedron
The cube is a hexahedron because it has 6 faces
If all the faces of a solid are the same size, then the faces are also considered congruent

 6.  Draw a polyhedron of your choice, and label the faces, edges and vertices

 7.   Which of the following does not name the diagram below?

(a) square              (b) cube                (c) polyhedron                  (d) solid

   Justify your answer. ____________________________________________________________

8.  (a) Dwayne identified all the following solids as polyhedra. Do you agree with Dwayne? YES/NO

                             

 

(b)  Justify your reason for your answer above. _____________________________________________

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