Definition
Pie chart
A pie chart divides one circle into sectors whose sizes show category shares of the whole data set.
View exact chart data
| Activity | Votes |
|---|---|
| Games | 4 |
| Drawing | 2 |
| Reading | 2 |
What it means
Think of the whole circle as all the data. Each category gets a sector whose size matches its share: twice the share means twice the angle. The sectors must fit together to make exactly one circle. In US materials, a pie chart may also be called a circle graph.
Remember it
Whole circle, whole data; bigger share, bigger sector.
Example
Eight children choose an activity: 4 choose Games, 2 Drawing, 1 Reading, and 1 Music. Games is 4/8 = 1/2, so its sector is 180°. Drawing is 90°, and Reading and Music are 45° each. The four angles total 360°.
Watch for
A circle split into decorative pieces is not a pie chart unless each piece corresponds proportionally to a category and all pieces represent one complete data set.
Common mix-up
Sector size comes from the category’s share of the total, not from the category’s order or label length.
Exact meaning
A pie chart is a part-to-whole data display made from sectors of one circle. Each sector’s central angle, and therefore its area, is proportional to that category’s frequency or fraction of the total; all sectors together represent the complete data set, 100%, or 360 degrees.