What is the primary function of a pie chart?

The primary function of a pie chart is to illustrate percentages of a whole. Pie charts are specifically designed to represent parts of a whole, effectively showing how individual segments contribute to the total. Each slice of the pie corresponds to a particular category, with the size of the slice representing its proportionate value compared to the entire pie, which symbolizes 100%. This visual format allows for an immediate understanding of relative sizes, making it easy to compare how much of the whole each category occupies.

In contrast, while comparisons between different quantities might be part of what pie charts do, they are mainly focused on how those quantities relate to the total, rather than just comparing them independently. Displaying changes over time typically relies on line graphs or bar charts, as those formats provide a clearer view of trends and fluctuations. Similarly, representing hierarchical information is more suited to tree diagrams or organizational charts, as pie charts do not convey relationships of dominance or subordination effectively. Thus, the strength of a pie chart lies in its ability to clearly convey the percentage breakdown of components within a whole, making the selected answer the most accurate reflection of its primary function.