Prisms

1
Prisms
20 November 2009
Here are two prisms
Its easy
This sounds difficult
Objective Calculate the volume of prisms
Vol. Area End x Length
2
Which of these shapes are prisms? Describe a
prism. A prism has
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Volume Area of the End x The Length
4
How to find the volume of a cuboid
Volume Base x Width x Height
V B x H x W V 4 x 10 x 2 V 80 cm3
10 cm
2 cm
4 cm
This cuboid has Base 4 cm Height 10
cm Width 2 cm
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First find the area of the end. Its a trapezium
so A (8 4) 2 x 10 A 12 2 x 10 A 6
x 10 A 60 cm2 Now multiply this by the length
to get the volume V 60 x 15 V 900 cm3
4
15
10
8
6
First find the area of the end. Its a circle
so A ?r2 A 3.14 x 5 x 5 A 78.5 cm2 Now
multiply this by the length to get the volume V
78.5 60 x 7 V 549.5 cm3
Radius 5 cm
Height 7 cm
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2. This tent is an approximate triangular prism.
What is its volume if it is 1.2 metres high, 1.5
metres wide and 2.4 metres long?
3
10
8
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1. Calculate the volume of this prism. Its end is
a trapezium.
3. Calculate the volume of this tin if it has a
radius of 8 cm and a height of 20 cm
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2. Area End 1.5 x 1.2 2 A. End 0.9
metres2 Vol A.End x Length Vol 0.9
x 2.4 Vol 2.16 metres3
3
10
8
7

• Area End (3 7) 2 x 8
• A. End 40 units2
• Volume A.End x Length
• V 40 x 10
• V 400 units3

• V Area x Length
• V pr2 x L
• V 3.14 x 82 x 20
• V 4019.2 cm2
• V 4019.2 millilitres

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Volume Area x Length Area Volume
Length Length Volume Area
V
A
L
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1. Here is a table that gives the dimensions of
six prisms. Copy and complete the table.
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1. Here is a table that gives the dimensions of
six prisms. Copy and complete the table.
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A tin of soup has a volume of 1000 cm3 and a
height of 15 cm. What is a) the area of its
end b) the diameter?

• A V L
• 1000 15 66.7 cm2
• A pr2
• ? r v(A p)
• ? r v(66.7 3.14)
• ? r 4.6 ? dia. 9.2

V
A
L