10 Surface Area and Volume PDF
10 Surface Area and Volume PDF
1 The measurements shown on the shapes below are in centimetres. For each shape, find
(correct to one decimal place if necessary):
i its perimeter ii its area
32
6
a b c
50
14
12
48
d e f
10 8 26 24 30 30
25 28
a 34 m to mm b 925 cm to m 1500 m to km
2 Convert:
c
d 3750 mL to L e 38 cm to mm f 7.5 L to mL
120°
130°
4 Calculate the volume of each prism (all units are in cm).
a b c d
15 20
15 45
A = 12 cm2 10
12 8
13
10.01
b c
9 16.8
a h w
p
40 7.5
19.5 21
Length Capacity
1 cm = 10 mm 1 L = 1000 mL
1 m = 100 cm = 1000 mm 1 kL = 1000 L
1 km = 1000 m 1 ML = 1000 kL = 1000 000 L
Mass Time
1 g = 1000 mg 1 min = 60 s
1 kg = 1000 g 1 h = 60 min = 3600 s
1 t = 1000 kg 1 day = 24 h
× 3600
× 1000 × 1000 × 1000
× 24 × 60 × 60
t kg g mg
÷ 1000 ÷ 1000 ÷ 1000
day h min s
÷ 24 ÷ 60 ÷ 60
÷ 3600
Example 1
Convert:
a 5.8 t to kg b 16 km to cm c 23 700 mL to L d 1500 min to h
Solution
a 5.8 t = 5.8 × 1000 kg To convert from large to small units, multiply (×).
= 5800 kg × 1000
t kg
16 km = 16 × 1000 × 100 cm
× 1000 × 100
b
= 1 600 000 cm km m cm
c 23 700 mL = 23 700 ÷ 1000 L To convert from small to large units, divide (÷).
= 23.7 L
÷ 1000
L mL
Digital memory
Metric prefixes are used in units of digital (computer) memory. A byte, abbreviated B, is the
amount of memory used to store one character, such as @, g, #, 7 or ?.
Unit Relationship Size
kilobyte (kB) 1 kB = 1000 B About half a page of text.
megabyte (MB) 1 MB = 1000 kB A million bytes, about the size of a novel.
gigabyte (GB) 1 GB = 1000 MB A billion bytes, about 500 photos or 7.5 hours of
video.
terabyte (TB) 1 TB = 1000 GB A trillion bytes, about the size of all of the books in a
large library.
Solution
a 3.2 MB = 3.2 × 1000 kB To convert from large to small units, multiply (×)
= 3200 kB × 1000
MB kB
b 147 000 MB = 147 000 ÷ 1000 GB To convert from small to large units, divide (÷)
= 147 GB
GB MB
÷ 1000
1
Length and distance
• One nanometre (nm) = m: your fingernails grown 1 nm every second, the
1 000000000
diameter of a helium atom is 0.1 nm
1
• One micrometre (μm) = m: used to measure diameters of bacteria
1 000000
• One astronomical unit (AU) = 149 597 871 km: the average distance between the Earth
and the Sun, used to measure distances between planets in our solar system
• One light year (ly) = 9.46 × 1012 km: the distance light travels in a year, for measuring
distances between stars
• One parsec (pc) = 3.0857 × 1013 km or 3.26 ly: for measuring distances between stars, the
nearest star Proxima Centauri is 1.30 parsecs away
1
Time
• One nanosecond (ns) = s: the time it takes electricity to travel along a 30 cm
1 000000000
wire
1
• One microsecond (μs) = s
1 000000
1
• One millisecond (ms) = s: the duration of the flash on a camera
1 000
• One decade = 10 years
• One century = 100 years
• One millennium = 1000 years
• One mega-annum (Ma) = 1 000 000 years: used in geology and paleontology, the
Tyrannosaurus Rex dinosaur lived 65 Ma ago
• One giga-annum (Ga) = 1 000 000 000 years: the Earth formed 4.57 Ga ago
Solution
a 0.73 s = 0.73 × 1 000 000 μs To convert from large to small
units, multiply (×)
10.01
= 730 000 μs
25 610 000 km = 25 610 000 ÷ 149 597 871 AU To convert from small to large
units, divide (÷)
b
= 0.17119…
≈ 0.17 AU
a
c Distance between 2 towns d Capacity of a car’s fuel tank
e Amount of water in a pool f Time taken to fly overseas
2 Convert:
750 g to mg b 36 kL to L 67 kg to g
R
EXAMPLE
a c
d 1.5 L to mL e 6.7 cm to mm 3.5 km to m
1
f
g 9.4 t to kg h 3.75 g to mg i 4.25 m to cm
j 0.2 kg to g k 26.2 L to mL l 0.3 km to m
m 3 kL to mL n 4 days to min o 15 hr to s
p 2.7 km to cm q 5 kg to mg r
0.7 m to mm
s 29.375 t to g t 18.14 km to mm u 3.27 g to mg
5 Convert:
a 8000 L to kL b 90 mm to cm c 180 s to min
d 240 min to h e 375 mL to L f 14 700 kg to t
g 8600 mg to g h 750 cm to m i 223 mm to cm
j 800 g to kg k 125 L to kL l 3.5 kg to t
m 17 000 000 mg to kg n 7200 min to days o 45 000 000 g to t
p 144 000 s to h q 86 400 s to days r 2500 cm to km
s 75 000 mL to kL t 34 700 mm to m u 628 L to ML
8 Convert:
4.8 MB to kB b 2.1 TB to GB 8.5 GB to MB
R C
EXAMPLE
a c
d 10.8 MB to B e 2910 B to kB 740 MB to GB
2
f
g 1050 kB to MB h 5900 GB to TB i 0.94 kB to MB
j 57 GB to MB k 0.43 GB to kB l 21 TB to GB
m 7.8 kB to B n 2180 MB to GB o 42 000 B to MB
p 940 MB to kB q 0.64 TB to kB r 278 MB to GB
9 Mala made a 3-minute phone call to her friend in Rockhampton using the Internet
at 3.3 MB per minute. How many kB did she use?
10 Ritu made a video call lasting 1 hours. If it used 3MB/min, how much data did the
call take?
1
4
terabyte (TB) 1 TB = 1024 GB 10244 = 1 099 511 627 776 B or 240 B (approx. one trillion)
{
Any measurement in the shaded region should be recorded as 12 cm. The measured length
is 12 cm, but the actual length is 12 ± 0.5 cm, meaning ‘12 centimetres, give or take 0.5
centimetres’ or ‘11.5 to 12.5 cm’.
The limits of accuracy of this ruler are ±0.5 cm or ‘plus or minus half a centimetre’.
Example 4
Find the limits of accuracy for each measuring scale.
a
25 mL
b
80 90 20
15
10
kg
5
Solution
a The size of one unit on the scale is 1 kg.
The limits of accuracy are ±0.5 × 1 kg = ±0.5 kg
b The size of one unit on the scale is 5 mL.
The limits of accuracy are ±0.5 × 5 mL = ±2.5 mL.
b
4
a
60 70 80 90 0 10 20 30 40 50 60 70 80 90 100 °C
mm
10.02
c d e
12
11 1
10 2
9 3
500
8 4
4
3
7 5
2
1000
6
0
1
cm
0
GRAMS
f g h
60
70
80 90 100 110
120
50 60 70
2000 gv
40 80
100 90 80 13
50 110 70 0
30 90
60
1500 g
120 50
0
13
14
20 100
40
100
0
150
40
30
14
1000 g
150
30
10 110
160
0
10 2
20
180 170 16
170 180
0 120
10
088724
km/h 500 g
0
0g
i j k F
mL 200 kL 7
6
150 5
4
100 3
2
50 1
E
2 What are the limits of accuracy for this measuring cylinder? 300 mL
Select the correct answer A, B, C or D.
A ± 0.5 mL 200 mL
B ± 10 mL
C ± 20 mL 100 mL
D ± 5 mL
3 Measuring with a ruler, Gemma correctly gives a measurement as 26.5 to 27.5 cm.
What is the size of a unit on the ruler?
R C
a
b What are the limits of accuracy of this measurement?
Using a ruler marked in millimetres, Emily gives the same measurement as 26.8 cm.
What are the limits of accuracy of this measurement?
c
h × perpendicular height
1
A = bh
w
2
l b
Example 5
For each composite shape, find:
i its perimeter ii its area.
7m
a b
38 cm
13 m 18 cm
11 m
6m
15 cm
Solution
Find any unknown lengths on the shape.
a i 11 – 6 = 5 7
Perimeter = 6 + 13 + 5 + 7 + 11 + 20
13
= 62 m 11
6
13 + 7 = 20
= 625
h = 625 18 18
= 25 cm
Perimeter = 18 + 25 + 38 + 15
= 96 cm 15
= 420 cm2
2
Example 6
This is the plan of a farm up for sale.
All measurements are in metres.
900
1500
10.03
a Find the area of the farm.
1900
b Express the area in square kilometres.
1800
c Find the area of the property in hectares, where 1 ha = 10 000 m2.
Solution
a Area = 900 × 1500 + 1900 × 1800
= 4 770 000 m2
c 1 ha = 10 000 m2
∴ Area = 4 770 000 ÷ 10 000
= 477 ha
11 m
57 mm
28 cm
6m
16 m
48 mm
5m
15 cm 22 m
32 mm
8 cm f
24
d e
c m
20 cm
9 cm
20 cm
52 cm
10 cm
30 cm
40
cm
11 cm
a b
4
4 cm cm 4 cm
15 cm
17 cm
12 cm
8 cm
11 cm
11 cm
24 cm 15 cm 4 cm 4 cm
11 cm
d e f 17 cm
10 cm
11 cm
9 cm
9 cm
5 cm
15 cm
8 cm
11 cm
16 cm
9 cm
20 cm
g 10 cm h i 34 cm
11 cm
2 cm
4 cm 12 cm
19 cm
20 cm
8 cm
17 cm
8 cm
j 12 cm 12 cm k l 20 cm
15 cm
22 cm
cm
12
24 cm
25 cm
.6
.6
12 cm
22
30 cm
50 cm
22 cm
cm
25 cm
15 cm
12 cm 12 cm
C 9 cm2 D 12 cm2
1 cm
a 0.5 cm b
3 cm 3.8 cm 3 cm
4 cm
6.4 cm 3 cm
19.6 cm
6 a Find the area of the large block of land shown in 800 m 10.03
the diagram (in m2).
b Express the area of the land in:
500 m
EXAMPLE
1300 m
6
i km 2
ii hectares
7 The area of a large rectangular property is 8.6 ha. Calculate the width if its length is
400 m. Select the correct answer A, B, C or D.
A 21.5 m B 215 m C 2150 m D 0.0215 km
Investigation
Area of a trapezium, kite and rhombus
1 Draw 2 copies of this trapezium onto a sheet
Side 1
a
of paper. Draw a dotted line, parallel to the
2
h
as shown. b
2 Cut out one trapezium and cut along the
dotted line to make 2 smaller trapeziums. Join the pieces to make a long parallelogram.
3 By measuring the height and base of the parallelogram to the nearest millimetre, find its area.
4 By comparing the measurements of the parallelogram to the measurements of the
original trapezium, suggest a general formula for finding the area of any trapezium.
Check your answer with your teacher.
5 Cut out the original trapezium and paste it and the parallelogram into your book.
6 Draw 2 copies of the kite and rhombus on a sheet of paper. Draw diagonals of length x and
y and label them as shown. Notice that they cross at right angles. For the kite, one diagonal
(x) is bisected by the other (y), while for the rhombus, both diagonals bisect each other.
1x 1x
2 2
1x 1y
y 2 2
1y
2 1x
2 x and y are the lengths
of the diagonals
h h
b
b
1
Area = base × perpendicular height Area = × (sum of parallel sides)
2
A = bh × perpendicular height
1
A = (a + b)h
2
Rhombus Kite
x y
y x
1
Area = × (product of diagonals)
2
1
A = xy
2
38 cm 14 m 30 mm
10.04
d 9m e
15 cm
10 cm
14 m
11 cm
Solution
1 1
Area of rhombus = × 38 × 20
2 2
a A = xy
= 380 cm2
b Area of parallelogram = 14 × 9 A = bh
= 126 m 2
1 1
Area of trapezium = × (16 + 30) × 12 A = (a + b)h
2 2
c
= 276 mm2
1 1
Area of kite = × 9 × 14
2 2
d A = xy
= 63 m2
1 1
Area of trapezium = × (10 + 15) × 11 A = (a + b)h
2 2
e
= 137.5 cm2
4m
6 cm
20 mm
8 cm
13.6 m
f
12 cm
d e
10 mm
1.5 cm
30 mm
25 mm
2 cm
7 cm
50 mm
4m
12 mm
22 mm
7 cm
m
64 mm
4.4
10.4 5m
4.4 c
7m
10.4
c m
2m 3m
cm cm
2 Find the area of each shape.
b
12 cm 62 mm
a c
49 mm
28 cm
17 cm
15 cm
54 m e f
20 mm
d
25 mm 23 cm
m
31 mm 25 mm
20 mm 31 cm
18
g h i
10 cm 14 m
14 cm 14 cm 9m
m
19 cm
m
32
3 Find the area of each shape.
a 9m b 5.5 m c 48 mm
7m 8m 20 mm
15 m 11 m 32 mm
d 16 m e f 2.1 m
10 m 10.5 cm 1.8 m
7.5 cm
22 m 1.4 m
6 cm
h i 20 mm
12 m
g
7 cm 14.5 m
35 mm
9 cm 6 cm 9.6 m
28 mm
A 10 cm B 15 cm 8 cm
C 17 cm D 12 cm
9 cm
5 Find the area of each shape.
13 cm c 5m
9m
4m
a b
5m 4m 7m 10 cm 8 cm 17 cm 5m 3m
10.04
4m 5m
3m
14 m 22 cm
5m
f 5.5 m
10 cm 10 cm
d e
6 cm 9.6 cm 6.6 m
8 cm 8 cm
8.8 m
10.5 cm
17 cm 17 cm
15 cm
5
a b
12
10 10 20 15 15
18.6 2
12 4.5
1.2
20
10.05
Circumference of a circle WS
C = π × diameter
C = 2 × π × radius
or
d
C = πd C = 2 πr
WS
r Worksheet
Homework
Back-to-front
problems
Area of a circle
The area of a circle is:
WS
A = π × (radius)2
Worksheet
Homework
Area and
perimeter
investigations
A = πr2
π = 3.141 592 653 897 93... and can be found by pressing the π key on your calculator. It has
Carpet talk
Example 8
For each circle, calculate correct to 2 decimal places:
i its circumference ii its area.
a b
8.5 m
20 m
Solution
a i C = π × 20 C = πd b i C = 2 × π × 8.5 C = 2πr
= 62.8318… = 53.4070…
≈ 62.83 m ≈ 53.41 m
ii A = π × 102 A = πr2 ii A = π × 8.52 A = πr2
= 314.1592… = 226.9800 …
≈ 314.16 m 2
≈ 226.98 m2
3m
Solution
1
This sector is a quadrant, a quarter of a circle. × circumference + radius + radius
4
1
a i
Perimeter = ×2×π×3+3+3
4
= 10.71238...
= 10.7 m
1 1
Area = × π × 32 × area of circle
4 4
ii
= 7.06858...
= 7.1 m2
80 80
b i Perimeter = × 2 × π × 4.2 + 4.2 + 4.2 × circumference + radius + radius
360 360
= 14.26430... There are 360° in a circle, but
= 14.3 m a sector is a fraction of a circle.
80 80
Area = × π × 4.22 × area of circle
360 360
ii
= 12.31504...
= 12.3 m2
240
c i Sector angle = 360° – 120° ii Area of sector = × π × 52
360
= 240° = 52.35987...
240
Perimeter = × 2 × π × 5 + 5 +
5 = 52.4 m2
360
= 30.94395...
= 30.9 m
• Arc length = × 2 πr
360
θ
arc length θ
• Perimeter of the sector = × 2 πr + r + r
360
θ r
12 m
22 m
10.05
30 m
Solution
a The shape is made up of a rectangle and b This ring shape is called an annulus, it
a quadrant. is the area enclosed by 2 circles with the
Radius of quadrant = 7 m same centre.
1
Length of rectangle = 22 – 7 Radius of large circle = × 30 m
2
= 15 m = 15 m
1
Area of shape = area of rectangle Radius of small circle = × 12 m
2
+ quadrant =6m
1
= 15 × 7 + × π × 72 Shaded area = large circle – small circle
4
= 143.4845… = π × 152 – π × 62
≈ 143.5 m2 = 593.7610...
≈ 593.8 m2
a b c d
8 cm 28.2 cm
30 cm
5.2 cm
a b c d
10 m 210°
120°
36 m 24 m
1m
10 m
6m 42 m
33 m 8 m 10° 8 m
30° 60°
6m
40 cm 22 mm
15 cm
12 cm
d
e 150 cm f
11 m 11 m 90 cm
65 cm 248 m
30 m 248 m
g
h 15 cm i
8 cm 18 cm
9 cm
7m 7m
18 cm
15 m
6 Calculate the area of the shape. Select the correct answer A, B, C or D.
EXAMPLE
10
7 cm
2 cm 2 cm
A 26.57 cm2 B 20.28 cm2 C 24.28 cm2 D 28.28 cm2
40
10.05
d e f
6 3 3
22
7 7 8
22 6
g h i
6 8 30
14
30
16
45
j k l
10 10 90
20
20
150 40
a
b If pavers are $165 per square metre laid, what is the cost of the path?
Shutterstock.com/Anatoliy Kosolapov
a
85 m
Izabella runs one lap in lane 1. What distance does she cover, correct to
one decimal place?
a
b Noah runs one lap in lane 2. What distance does he cover, correct to one
decimal place?
By how much should the start line be staggered in lane 2 (from lane 1)
so that Izabella and Noah run the same distance in one lap?
c
Because π is an irrational number, its decimal digits run endlessly without repeating. Over
history, mathematicians and scientists (and now computer scientists) have tried to calculate
more accurate values of π, using more sophisticated formulas and calculation techniques.
The ancient Greeks, Romans and Chinese first estimated π as 3. This value is also mentioned
in the Bible. Since the first computer, the ENIAC, was invented in 1949, much progress has
been made. Supercomputers have been used to calculate more decimal places of π and, in
2019, Emma Haruka Iwao (Japan), working for Google, calculated π to over 31.4 trillion
places. In 2015, Suresh Sharma (India) memorised π to 70 030 decimal places. It took him
17 hours 14 minutes to recite it.
Research the modern history of π and find out about recent calculations of its value.
Worksheet
Homework
Surface area
Example 11
Calculate the surface area of each prism.
WS
4 cm 12 cm
4 cm
12 cm 5 cm
Solid
4 cm 4c
shapes
8 cm
m
25 cm Presentation
Surface
area
Solution
a A cube has 6 identical faces in the shape of a square. 6 × area of a square
Surface area = 6 × 42
Technology
Surface area
= 96 cm2
calculator
Surface area
calculator
Example 12
Calculate the surface area of each triangular prism.
5 cm
a b
3 cm
Surface area
of a prism
10 cm
8 cm 24 m
nm
30 m
Surface area
10 m
of prisms
Solution
a This triangular prism has 5 faces: 2 identical triangles 3 cm
5 cm
(front and back), 2 identical rectangles (sides) and
8 cm
another rectangle (bottom). Drawing the net of the
prism may help you see this. 10 cm
1
Surface area = (2 × × 8 × 3) + (2 × 10 × 5) + (8 × 10) Front and back faces +
2
= 204 cm 2 side faces + bottom face
18 cm
24 cm
10.06
Solution
This trapezoidal prism has 6 faces: 2 identical 10
trapeziums (front and back), 4 different 12
10
rectangles. 24
15
13
18
1
Area of each trapezium = × (10 + 24) × 12
2
= 204 cm2
Surface area = (2 × 204) + (18 × 10) 2 trapeziums + 4 rectangles
+ (18 × 15) + (18 × 24)
+ (18 × 13)
= 1524 cm2
g h
4 Name the prism that each net represents, then calculate the surface area of the prism.
All lengths are in metres.
EXAMPLE
12
a b 15
12
21 6
13
24 26 25
24
c d
13
45
30
51 66
72
a cube c
45 cm
6.5 m 144 cm
20 cm
18 cm
35 mm
3.4 m
7.5 m 48 mm
65 mm
5.2 m
44 cm 10.06
10 m 29 cm
10 m
a b c
15 cm
h
8m 6m 40 cm
7m
15 m
16 m
6m
8 cm f 9m
m
.5 c
d e
3
r
3.7 cm 12 m
15 m
10 m
5m
12 m
19
a
b Yasmin bought material at $12 per square metre. 7c
How much did it cost her for the material to make the tent? m m
0c
21
180 cm
160 cm
8 5 cubes of side length 1 cm are joined to make this solid.
What is the surface area of the solid? Select the correct
answer A, B, C or D.
A 17 cm2 B 18 cm2
C 5 cm2 D 22 cm2
14
13
52
a
20
20
24 48 2048 15 12
17 40
32 10
Investigation
Surface area of a cylinder r
Can 2
= 2πr
circumference
Surface area of a cylinder = area of 2 circles
height, h 10.07
WS
+ area of rectangle
SA = 2 × πr2 + 2πr × h
Worksheet
Homework
r Applications
of area 3
= 2πr2 + 2πrh
SA = 2πr2 + 2πrh
where r = radius of circular base
height, h Technology
Surface area
h = perpendicular height
calculator
The area of the 2 circular ends = 2πr2 and the area of the curved surface = 2πrh.
Surface area
calculator
Example 14
Find, correct to one decimal place, the surface area of a cylinder with diameter 12 cm and
Surface
height 20 cm.
area of a
cylinder
Solution
Radius = 1 × 12 cm 1 of diameter
2 2
= 6 cm
20 cm
12 cm
Surface area = a rea of 2 ends + area of the curved surface
SA = 2 πr 2 + 2 πrh
= 2 × π × 62 + 2 × π × 6 × 20
= 980.1769...
≈ 980.2 cm2
12 cm
r = 6 cm
circumference
height
curved surface
end
Solution
1
Surface area = 2 semicircle ends + × curved surface
2
end
SA = 2 × ( 1 × π × 0.52 ) + 1 × (2 × π × 0.5 × 3)
2 2
= 5.49778... surface 3 m
curved
≈ 5.50cm2
0.5 m
2 Find, correct to one decimal place, the curved surface area of a cylinder with:
a diameter 9 cm, height 32 cm b radius 85 mm, height 16 mm
3 Calculate, correct to one decimal place, the surface area of each solid. All lengths shown
are in metres. PS R
EXAMPLE
one open
openend
a c
cylinder with one
closed cylinder end closed half-cylinder
0.37
25 16.2
1.5
29.3
15
d half-cylinder e half-cylinder with f cylinder open
with
openopen
top top top, open top, one end open at both
both ends
half-cylinder with half-cylinder with open cylinder open at
1.2 1.5
one end open ends
2.85 5.75
30
12
6m
b the number of whole litres of paint needed
if coverage is 9 m2 per litre.
b
2.24 m
a
2m
5m
2m 5m
2m
20 cm
The capacity of a container is the amount of fluid (liquid or gas) it holds, measured in
millilitres (mL), litres (L), kilolitres (kL) and megalitres (ML).
Worksheet
Homework
Volume and
capacity
3
volume?
1 m3 contains 1000 L or 1 kL 1 mL
1 m3 = 1 kL
1 cm3 × 1 000 000 =
Formula
matching
game
An end face of a prism is called its base. Prisms take their names from their base and cross-
section. For example, this prism is a trapezoidal prism because its base and cross-sections are
trapeziums.
base cross-section
Trapezoidal prism
Volume of a prism
V = Ah
where A = area of base
h = perpendicular height
A h
Example 16
Find the volume of each prism.
b
15 cm 4 cm
a c
30 cm 3m 4c
Volumes of
10 m
3 cm
prisms and
42 cm 6 cm
cylinders m
5m
1
A = × 5 × 3 Area of a triangle.
2
b
= 7.5
V = 7.5 × 10 V = Ah, where height h = 10
= 75 m
10.08
3
1
A = × (4 + 6) × 3 Area of a trapezium
2
c
= 15 cm2
V = 15 × 4 V = Ah, where height h = 4
= 60 cm 3
Example 17
A storage box in the shape of a rectangular
prism is 110 cm long, 65 cm wide and
70 cm
70 cm high.
a Find the volume of the box in cm3.
b What is the volume in m3? 110 cm
cm
65
Solution
a V = 110 × 65 × 70
= 500 500 cm3
Alternatively, you could convert
b 1 m = 100 cm, so 1 m3 = 1003 cm3 = 1 000 000 cm3
110 cm, 65 cm and 70 cm to metres,
∴ V = 500 500 ÷ 1 000 000 then multiply them together for the
volume.
= 0.5005 m3
Volume of a cylinder
A cylinder is like a ‘circular prism’ because its cross-sections are identical
circles. Because of this, we can also use V = Ah to find the volume of a
r
V = πr2 × h
= πr2h
Volume of a cylinder
V = πr2h
where r = radius of circular base
h = perpendicular height
Solution
a Radius = 1 × 128 cm 1 of diameter
2 2
= 64 cm
V = π × 642 × 241 V = πr2h
= 3 101 179.206…
≈ 3 101 179 cm3
b Capacity = 3 101 179 mL 1 cm3 = 1 mL
= (3 101 179 ÷ 1000 ÷ 1000) kL
= 3.101 179 kL ÷ 1000 ÷ 1000
kL L mL
≈ 3.1 kL
4m 60 mm
40 cm
5m
22 25 mm
40 mm
15 cm
cm
d e f
0.6 m
30 cm
1.2 m 1.8 m
32 mm 14
cm
2 The volume of a cube is 125 000 cm3. Convert this to m3. Select the correct
answer A, B, C or D.
A 1250 m3 B 12.5 m3 C 1.25 m3 D 0.125 m3
EXAMPLE
17
3 The volume of a small jewellery box is 160 000 mm3. Which expression gives its volume
in cm3? Select the correct answer A, B, C or D.
A 160 000 ÷ 103 B 160 000 ÷ 100
C 160 000 ÷ 100 2
D 160 000 ÷ 102
converting to m3
a
a A = 63.1 m2 b c 64 cm
8m 38 cm
A = 27.5 cm2 A = 312 cm2
15 cm
1.6 m
35 mm 0.8 m
12
mm
d e f
1.5 m 37
cm
3.5 m
8m 4.8 m
45
cm
7 Calculate, correct to one decimal place, the volume of each solid. All lengths are in
metres.
a 1.8 2.4 b 25 c
f
5.2
d e
2.7 m
C 6280 L D 16 964 L
9 A triangular prism has base length 15 cm, height 8 cm and volume 630 cm3.
What is its length? R
10 A fish tank that is 55 cm long, 24 cm wide and 22 cm high is filled to 4 cm below the top.
Calculate the amount of water in the tank in litres.
Shutterstock.com/John Wollwerth
correct to the nearest cm3. 6
10
6
15
6
20
1.29 m
Shutterstock.com/
2m
Stephen Rees
1.64 m
13 This swimming pool is 15 m long and 15 m
10 m wide. The depth of the water 10 m 1m
ranges from 1 m to 3 m.
Calculate the capacity of this pool in 3m
kilolitres.
14 Robyn and Anthony are planning to make a
raised vegetable garden. If the dimensions
of the garden bed are 7.5 m × 9 m × 60 cm,
calculate how much soil they will need to buy.
Select the correct answer A, B, C or D.
Shutterstock.com/
Alison Hancock
A 405 m3 B 40.5 m3
C 4050 cm3 D 4050 m3
9.5 cm
10.08
a Find the average diameter of a tennis ball.
b The tennis balls are packed in cylinders as shown. Using the larger diameter,
calculate the radius and height of one cylinder.
i To find the volume of the cylinder, its radius and height are rounded up to one
decimal place. Explain why, and write the radius and height rounded up.
c
Investigation
Volume vs surface area
You will need: At least 20 centicubes
1 Copy the following table.
2 Build as many rectangular prisms as you can with a volume of 8 cubes, but with different
dimensions. Note: 1 × 1 × 8 is the same as 1 × 8 × 1 and 8 × 1 × 1.
3 Record your dimensions in the table and calculate the surface area of each prism.
4 What are the dimensions of the solid that has the smallest surface area?
5 What name do we give to this solid?
6 Repeat the experiment for a volume of:
a 12 cubes b 20 cubes.
10
• To find 10% or of a number, divide by 10.
• To find 5% of a number, find 10% first, then halve it (since 5% is half of 10%).
• So to find 15% of a number, find 10% and 5% of the number separately, then add the
4
To find 25% of a number, halve the number twice as 25% = .
5 Study each example.
a 25% × 700 b 25% × $86
1 1
50% × 700 = × 700 = 350 50% × $86 = × $86 = $43
2 2
1 1
25% × 700 = × 350 = 175 ∴ 25% × $86 = × $43 = $21.50
2 2
12 1 % × 400 12 1 % × $144
2 2
a b
1 1
50% × 400 = × 400 = 200 50% × $144 = × $144 = $72
2 2
1 1
25% × 400 = × 200 = 100 25% × $144 = × $72 = $36
2 2
1 1
12 1 % × 400 = × 100 = 50 12 1 % × $144 = × $36 = $18
2 2 2 2
Technology
Approximating the volume of a pyramid Technology
Measuring
10
6
8
We will create a spreadsheet that approximates the volume of a rectangular pyramid with a
base of length 8 units and width 6 units, and a perpendicular height of 10 units.
The volume of each layer can be easily calculated using V = lwh. Finding the sum of the
layers will then give an approximation of the volume of the pyramid.
Let n be the number of layers. Then the height of each layer is 10 .
The length and width of each layer decreases from 8 units and 6 units by a constant amount
n
A B C D E F
1 Number of
layers
2
3 Height Length Width Thickness of Volume of Sum of
layer layer volumes
4 10 8 6 =$A$4/$D$2 =B4*C4*D4 =E4
5 =B4-$B4/$D$2 =C4-$C$4/$D$2 =E5+F4
6
13
2 a To divide the volume of the pyramid into 10 layers, enter 10 in cell D2.
b Copy each formula down to row 13.
c Explain the results in cells E13 and F13.
d How accurate was your result in F13? Explain.
e Print out your spreadsheet.
To divide the pyramid into 40 layers to calculate a better approximation, enter 40 in
cell D2 and copy each formula down to row 43.
3 a
b In one or 2 sentences, compare your volume approximation in F43 with the previous
approximation in F13.
4 a Enter each of these values in cell D2, copy the formulas down to the appropriate
row and write down the approximation for the volume of the pyramid.
i 100 (copy down to row 104)
ii 200 (copy down to row 204)
iii 400 (copy down to row 404)
1
b Use the formula V = Ah to calculate the exact volume of the pyramid.
3
c Write a brief report about your results in parts a and b.
WS
Worksheet
Homework
Back-to-front
10.09
problems
(Advanced)
Volume of a pyramid
1
3
V= Ah h
where A = area of base
h = perpendicular height
A
Example 19
Find the volume of each pyramid.
a b
30 mm
8m
20 mm
25 mm 7m
10 m
Solution
A = 25 × 20 Area of rectangular base
= 500 mm2
a
1 1
V = × 500 × 30 V= Ah, where height h = 30
3 3
= 5000 mm3
1 Area of triangular base
× 10 × 7
2
b A=
= 35 mm2
1 1
V = × 35 × 8 V= Ah, where height h = 8
3 3
1
= 93 m3
3
h 40 mm
Solution
First find h, the perpendicular height of the pyramid. 64 mm
Example 21
The volume of a square pyramid is 100 cm3. If its height is 12 cm, calculate the length of its base.
Solution
Let the length of the square base of the pyramid be x cm.
1
V = Ah
100 = × x2 × 12 x = 25
3
1
100 = 4x 2 =5
3
= 25
4
Volume of a cone
A cone is like a ‘circular pyramid’ so:
1
Volume = Ah
3
1
V = × πr2 × h
3
1 2
= πr h
3
1 2
V = πr h
3
where r = radius of circular base and h = perpendicular height
h
10.09
Example 22
Calculate the volume of the cone, correct to the nearest cm3.
30 cm
21 cm
Solution
V = × π × 10.52 × 30 V = πr2h, where r = × 21 = 10.5
1 1 1
= 3463.6059…
3 3 2
≈ 3464 cm3
Example 23
A cone has a slant edge of 61 mm and a base radius of 61 mm
11 mm. Find its volume, correct to one decimal place. 11 mm
h
Solution
First, find the height, h.
h2 = 612 – 112 Using Pythagoras’ theorem
= 3600
h = 3600
= 60
1 1 2
V= × π × 112 × 60 V= πr h
3 3
= 7602.6542…
≈ 7602.7 mm2
7 cm
EXAMPLE
10 cm
19 a b c
9 cm
8 cm
9 cm
10 cm
8 cm 8 cm
d e f
15 cm 8m
8m
14 m
12 cm 8m
20 cm
5m
18 m
41 mm 41 mm
a b c
52 m
26 cm 25 m
30 m
h
9 mm 9 mm
h
20 cm 96 m
20 cm
160 cm
126 cm
d e f
68 mm 61 mm 8.5 m 8.5 m
116 cm
11 mm
11 mm 3.6 m 3.6 m 105 cm
32 mm 32 mm 3.6 m 3.6 m
Shutterstock.com/Jeremy Red
147 m
Find the volume in cubic metres if the
original height of the pyramid was 147 m.
a
5 The area of the base of a pyramid is 40 m2. If its volume is 360 m3, calculate its
perpendicular height. R
6 The volume of a square pyramid toy is 1620 mm3. If the length of its base is 8 mm,
EXAMPLE
21
7 A square pyramid has a volume of 80 cm3 and a height of 10 cm. Calculate, correct to
one decimal place, the length of the base of the pyramid. R
15 mm
14 cm
8m
18 mm
17 cm
5m
7 cm 10 cm
d e f
12 cm
15 cm 30 mm
18 mm
8 cm 10.8 cm
35 m
4 cm
0.8 m
68 m
d e f
83 cm
247 m
3.6 m
83 cm
12 cm
6m
a b c
20 cm
15 cm
3m
8 cm
11 A cone has a volume of 1468 cm3 and a base radius of 12 cm. Find its height, correct to
one decimal place. R
12 A cone has a volume of 820 m3 and a perpendicular height of 10 m. Find its radius,
correct to one decimal place. R
13 A cone has a volume of 150 m3. If the height and radius of the cone are equal in length,
calculate the radius of the cone. Give your answer to 2 decimal places. R
b its area
3 A rhombus has diagonals of length 24 cm
D C
A B
qualifying area
disqualifying
small circle has a radius of 1 m. area
40 m
8 12
8 6
9
6 The 3 faces of a rectangular prism have areas as shown.
Calculate the volume of the prism. 40 cm2
20 cm2 32 cm2
7 A cube opened at one end has an external surface area of 1125 cm2. Find its volume.
8 A 10 m flat square roof drains into a cylindrical 10 m
rainwater tank with a diameter of 4 m.
If 5 mm of rain falls on the roof, by how much
(to the nearest mm) does the level of water 10 m
in the tank rise?
4m
9 Calculate, correct to one decimal place, the volume of a tetrahedron with a side
length of 24 cm.
Language of maths
arc length base capacity circumference
cross-section curved surface diagonal diameter
Surface
crossword
Topic summary
• Write 10 questions (with solutions) that could be used in a test for this chapter. Include some
WS
• Swap your questions with another student and check their solutions against yours.
Surface area
and volume
• List the sections of work in this chapter that you did not understand. Follow up this work
(Advanced)
Limits of accuracy of
measuring instruments
1 Convert:
8 km to m b 15 min to s 0.7 m to mm
10.01
a c
d 250 000 g to kg e 8.4 GB to MB f 9.5 t to kg
g 300 min to h h 34 000 B to kB i 125 kL to L
2500 cm to km k 17 000 000 kg to t 8900 GB to TB
TEST YOURSELF 10
j l
m 10 500 ms to s n 9.1 millennia to years o 2.6 Mm to m
p 3 ly to km q 0.000 000 4 s to μs r 75 000 000 μm to m
Shutterstock.com/DG-Studio
iStock.com/AlonzoDesign
c d
Shutterstock.com/Uros Jonic
iStock.com/AndrewScherbackov
18 mm
25 cm
13 m
17 cm
7m 15 cm
9 cm
18 cm
12 mm
15 m
12
8mcm 20 cm
75 mm
18 mm
17 m
34 mm
15 m
16 cm
18 mm
80 mm
12 mm
12 mm 9 mm 9m
a c
4 cm 40 mm
10.3 m
3 cm 10 cm 9 mm
5.7 m
8 mm e
TEST YOURSELF 10
12 m 5 m
d f P Q
PR = 20 cm
12 mm 12 m SQ = 26 cm
5m
9 mm 16 mm
S R
11 cm 16 m
24 mm
48 mm 12 m
d e f
20 mm
b c
9 mm 11 cm
15 cm
15 m
prism
4m 24 m
16 m
8m 30 m
5.5 m 14 m
3.2 m 8m
2.7 cm
Cylinder, 4.8 cm
21 m
23 mm
open at
35 m one end
TEST YOURSELF 10
11 Calculate, correct to 2 decimal places, the volume of each cylinder above. 10.08
13 cm
35 cm
24 cm
14 Find the volume of each pyramid. STAGE 5.3
a b c
12 cm
10.09
15 cm
8m
11 m 15 cm 18 cm 9 cm 14 cm
11 m
32 cm
10.09
a b c
20 mm
20 cm
48 mm
cm
37
8 cm
16 A cone has a volume of 115 cm3 and a base radius of 3.2 cm. Find, correct to one decimal
place, the height of the cone.
10.09