Pie Charts
Why a Pie Chart?
□ Very visual
□ Easy to read
□ Slices show clearly how the data is
distributed
Data for a Pie Chart
□ Usually given in
a table format
□ This data was
obtained from a
class survey on
“Favourite
Drinks”
These are the
answers given
Other allows for
“unexpected”
answers
Favourite
Drink
How many
Milk said they
people
preferred this
drink
Orange
Frequency
7
9
Cola
13
Water
6
Tea
2
Other
3
1 Work out the slices
Favourite
Drink
Milk
Frequency
7
Orange
9
Cola
13
Water
6
Tea
2
Other
3
Total 40
We need to calculate
the size of each slice in
the pie chart
40 people responded
to the survey
If very person had their
own slice, each would
get the same
1
40
the circle
Xof360º
= 9º
If 1 person is 9º
Favourite
Drink
Milk
Frequency
Angle
7
7 x 9 = 63º
Orange
9
9 x 9 = 81º
Cola
13
13 x 9 = 117º
Water
6
6 x 9 = 54º
Tea
2
2 x 9 = 18º
Other
3
3 x 9 = 27º
Total 360º
2 Draw the Pie Chart
xx
Mark
Draw
Use
Or draw
compasses
a
a centre
circle
around
with
foran
the
centre
Angle
Pie Chart
on
Measure
the mark
2 Draw the Pie Chart
Draw line vertically from
centre to circumference
Draw LARGEST slice first
i.e. Cola = 117º
x
Cola
Label the slice ‘Cola’
Do not enter the angle or the frequency!
2 Draw the Pie Chart
Draw NEXT LARGEST slice
i.e. Orange = 81º
Turn Protractor so that
0º marker is at the end
of line just drawn
Cola
Orange
2 Draw the Pie Chart
Then Milk = 63º
Cola
Milk
Orange
2 Draw the Pie Chart
Then Water = 54º
Water
Milk
Cola
Orange
2 Draw the Pie Chart
Then Other = 27º
Water
Milk
Cola
Orange
2 Draw the Pie Chart
The LAST slice is already
drawn – just check it
Tea = 18º
Give the Pie Chart
its Title
Water
Milk
Cola
Orange
Class 7A’s Favourite Drink
Remove the small guide marks carefully