Categories in a pie chart that represent parts of the whole and show the contribution of each value to the total.

The categories in a pie chart are represented by different 'slices' of the pie. Each slice corresponds to a particular value from the data set. The size of each slice is proportional to the percentage that this value contributes to the total.

Here are the steps to create a pie chart:

1. Collect Data: Gather the data that you want to represent in the pie chart. This data should be categorical, meaning it can be divided into different categories.

2. Calculate Percentages: For each category, calculate its percentage of the total. To do this, divide the value for that category by the total of all values, then multiply by 100.

3. Draw the Chart: Draw a circle to represent the whole pie. This circle will represent the total of all values.

4. Divide the Pie: Divide the pie into slices according to the percentages you calculated. Each slice represents a category from your data. The size of the slice corresponds to its percentage of the total.

5. Label: Label each slice with its category and percentage. This helps viewers understand what each slice represents.

6. Color: You can also color each slice differently to make the chart easier to read.

Remember, a pie chart is best used when you want to show how individual parts contribute to the whole, and when you have relatively few categories. If you have many categories, or if the values are very close to each other, a different type of chart may be more effective.