Pie charts are served up daily in
newspapers, on television, in magazines,
and in math and social studies lessons.
They are also known as circle graphs and
are easy to interpret if you learn how
to identify the parts.
In a pie chart or
circle graph, the first thing you need to
read is the title.
This will be in bigger,
darker print and is usually above the
graph.
There may or may not be some
explanation following the title.
If there
is, be sure to read it completely to help
you understand what is being explained.
After the title, look for the labels or
the key like a legend on a map.
These
tell what each piece of the pie
represents.
A label might be directly on
the section of pie.
The labels might appear as a key.
Sometimes the key will use colors, but
sometimes shading will be used to show
the different sections.
The third part
you will need to identify is the source.
The source is usually found at the
bottom of the pie chart.
It simply tells
you from where the information for the
graph came.
Now that you have identified the parts
of the graph, think about how the pieces
fit together.
The whole pie equals 100
percent of the topic.
The size of each
section depends on what part of 100 it
is.
For example, if you want to show that
half the people in a community vote, you
would think of half of 100, or 50%.
Likewise, the remaining 50 out of 100
would be labeled to see the full picture.
Perhaps 25% of the people don't want to
vote and 25% are ineligible.
The result
would fill up 100% of the pie.
The graph
may have the % figures as part of the
label to help the reader summarize the
data.
In the following graph, 100% of the
pie means the entire 2.13 trillion
budget proposed by President Bush for
the 2002 budget.
Each section of the pie
represents how many dollars went to each
category.
When you add all the sections
together, they equal 2.128
rounded to 2.13 trillion.
In this
case, the actual amounts are used rather
than the percent of each amount.
In the following pie charts, percentages
are used.
100% represents all the people
polled.
You have completed this activity on pie
charts.
