Circle Graphs
How do you spend your day? How did the class vote? When data splits one whole into parts, a circle graph (sometimes called a pie chart) shows each part as a slice. Learn how to read slices as fractions and percents, figure out how many are in each part, and make a circle graph of your own. Then practice with three activities.
Parts of a Whole
The whole circle stands for all of the data: every student surveyed, every dollar spent. Each slice is one category. The bigger the slice, the bigger that category's share of the whole.
A class of 24 students voted for their favorite season. Tap a slice to read it.
Seeing Fractions in a Circle
A few slice sizes are easy to spot, and they help you estimate any slice:
Percents in a Circle Graph
Circle graphs are often labeled with percents. Percent means "out of 100," so the whole circle is 100%. That means all the slices must add up to exactly 100%.
If you know the total, you can use a slice's percent to find how many are in that part. Multiply the total by the percent written as a fraction.
Making a Circle Graph
To turn data into a circle graph, figure out what fraction of the whole each category is. Here's how 20 students got to school:
the data splits one whole into parts, like how a group voted or how money was spent. The parts must add up to the whole.
you want to compare exact amounts across groups. Bar graphs make small differences easier to see.
one thing changes over time, like temperature through the day. See Line Graphs.
Practice
Three ways to practice: read circle graphs, build them yourself, and match data to the right graph.
Read the Circle Graph
Use the slices, the percents, and the total to answer each question.
Build the Circle Graph
Drag the white handles around the circle to size each slice so it matches the table. Slices snap to steps of 5%.
Match the Data
Look at the table, then pick the circle graph that shows the same data. No percents are printed, so compare the slice sizes!