Objective: To develop and use a Objective: To develop and use a formula for the volume of a formula for the volume of a

rectangular prismrectangular prism

Volume of RectanguVolume of Rectangular Prismslar Prisms

What is volume?What is volume?

• The volume of a solid object such as a brick The volume of a solid object such as a brick or a ball is a measure of how much space the or a ball is a measure of how much space the object takes up. The volume of a container object takes up. The volume of a container such as a box is a measure of how much the such as a box is a measure of how much the container will hold.container will hold.

VolumeVolume

• VolumeVolume – the amount of space occupied by – the amount of space occupied by an object.an object.

Example: Example: The VOLUME of this The VOLUME of this cube is all the space cube is all the space contained by the sides contained by the sides of the cube, measured of the cube, measured in cube units (unitsin cube units (units33).).l

w

h

The Volume of a Rectangular PrismThe Volume of a Rectangular Prism

1”1”

1”

2.0”

3.0”

2.0”

"2"2"3.

.

.

prismrect

prismrect

prismrect

Volume

hwlVolume

HeightwidthlengthVolume

Volume = 12 inVolume = 12 in33

VolumeVolume

• VolumeVolume – the amount of space occupied by – the amount of space occupied by an object.an object.

Example: Example: The VOLUME of this cube The VOLUME of this cube is all the space contained is all the space contained by the sides of the cube, by the sides of the cube, measured in cube units measured in cube units

(units(units33).).lw

h

VolumeVolume

• Volume Volume – To calculate the volume of a prism, we first To calculate the volume of a prism, we first need to calculate the area of the BASE of the prism.need to calculate the area of the BASE of the prism.

Example: The Example: The AREA AREA of the of the base of this rectangular base of this rectangular

prism is prism is l x w.l x w.

lw

h

Volume

• VolumeVolume – Once we know the area of the base, this – Once we know the area of the base, this is then multiplied by the height to determine the is then multiplied by the height to determine the VOLUME of the prism.VOLUME of the prism.

We find that: We find that:

Volume = Area of Base x HeightVolume = Area of Base x Height

Volume = (l x w) x hVolume = (l x w) x hlw

h

VolumeVolume

• VolumeVolume (Rectangular PrismRectangular Prism)

Formula: Formula:

V = l x w x hV = l x w x h

= - cubic. unit= - cubic. unitl

w

h

VolumeVolume

• Find the volume of this prism…Find the volume of this prism…

Formula: Formula:

V = l x w x hV = l x w x h

= 7 x 5 x 4 = 7 x 5 x 4

= 140 cubic. cm= 140 cubic. cm

5 cm4 cm

7 cm

VolumeVolume

• Find the volume of this prism…Find the volume of this prism…

Formula: Formula:

V = l x w x hV = l x w x h

= 6 x 5 x 8= 6 x 5 x 8

= 240 cubic. cm= 240 cubic. cm6 cm

5cm

8 cm

Let’s talk about it.Let’s talk about it.

Open you’re my Open you’re my word of Math to word of Math to page 239page 239 Complete pages Complete pages 241 -250 with 241 -250 with your partner.your partner.

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