PrismsLesson 9-2

2 Truths and a fib!

1. A cylinder is not a polyhedron.

3. A square pyramid has 5 faces.

2. A cube is a type of pyramid.

What is a prism? A prism is a 3D figure with parallel basesthat are polygons. The other faces of a prismare parallelograms, most often rectangles.

The name of a prism tells what the baseshould be shaped like:

– Triangular prism – triangle bases – Rectangular prism – rectangle bases – Cube – square bases – Pentagonal prism – pentagon bases

Vertices

(points)

Edges (lines)

Faces (planes)

8

1212

66

The base has sides.

44

Vertices

(points)

Edges (lines)

Faces (planes)

6 6

99

55The base has 33 sides.

Vertices

(points)

Edges (lines)

Faces (planes)

1212

1818

88

The base has sides.

66

Vertices

(points)

Edges (lines)

Faces (planes)

1010

1515

77

The base has sides.

55

Name Picture Base Vertices Edges Faces

Triangular Triangular PrismPrism

Rectangular Rectangular PrismPrism

Pentagonal Pentagonal PrismPrism

Hexagonal Hexagonal PrismPrism

Heptagonal Heptagonal PrismPrism

Octagonal Octagonal PrismPrism

33 66 99 55

44 88 1212 66

55 1010 1515 77

66 1212 1818 88

77 1414 2121 99

88 1616 2424 1010

Any PrismAny Prism nn 2n2n 3n3n n+2n+2

Draw itDraw it

No No picturepicture

Volume of a Prism = Bhwhere B = Area of the Base and h = Height of the

Prism Remember: the bases are the parallel sides and the height is the distance between the bases!!!

Height of the prism

Base Base

BaseBase

Volume of a Cube

Side length is 5 inches

Volume= area of base x heightV = Bh (B= AREA of the base)

Area of the base=5(5) =25Height=5Volume= 125 cubic inches

Area of the base=?Height=?Volume= ?

Volume of a Rectangular Prism

V = area of base x heightV = Bh (B= AREA of the base)

54

8

Area of base =5 x 4 = 20Area of base =5 x 4 = 20H = 8H = 8

V = 20 x 8 = 160V = 20 x 8 = 160

Area of base =?Area of base =?Height = ?Height = ?

Volume = ?Volume = ?

Triangular PrismVolume

Area of the base=?Triangle ½(6)(4) =12

Volume = BhVolume = Bh

6

8

5

10

4

Height of prism= ?Height of prism= ?

Volume = area of base x heightVolume = area of base x height

Height of prism= 10

Volume= (12)10=120 cubic units

Go to the Notes to see another example!

What do you say when you see an empty parrot cage?

Poly-gon