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
Length
Volume Area of the end x Length
Area of the end
3
To do this work, you will need to know how to
calculate the area of these five shapes
A BH/2
A BH

• Rectangle
• Triangle
• Parallelogram
• Trapezium
• Circle

A h(a b)/2
A ?r2
4
Volume Area End x Length
V Area End x Length V 4 x 2 x 10 V 8 x
10 V 80 cm3
10 cm
2 cm
4 cm
5
Volume Area End x Length
The end is 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
The end is 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
Length 7 cm
7
Volume Area x Length Area Volume
Length Length Volume Area
V
A
L
1. Here is a table that gives the dimensions of
six prisms. Copy and complete the table.
8
Volume Area x Length Area Volume
Length Length Volume Area
V
A
L
1. Here is a table that gives the dimensions of
six prisms. Copy and complete the table.
9
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?
4. 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?
5. A tin 5000 ml of paint and is used to paint a
wall with an area of 35 metres2. How thick is the
paint on the walls?
3. Calculate the volume of this tin if it has a
radius of 8 cm and a height of 20 cm
10
4. a)1000 15 66.7 cm2 b) A pr2 ? r v(A
p) ? r v(66.7 3.14) ? r 4.6 ? dia. 9.2
2. V Area x Length V 1.2 x 1.5 2 x 2.4
V 2.16 metres3
5. 35 metres2 350000 cm2 1 ml 1 cm3 5000 ml
5000 cm3

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

350000 cm3
L V/A L 5000/350000 L 0.014 cm