Which type of graphs represent values as percentages of a whole?

The pie chart is designed specifically to represent values as percentages of a whole, making it the most effective choice for visualizing proportions. Each segment of the pie corresponds to a specific category and the size of that segment is directly proportional to the category's percentage of the total. This visual format enables viewers to easily compare different categories at a glance and understand how they relate to the entire dataset.

In contrast, a bar chart displays individual quantities for each category, making it good for comparing absolute values rather than their proportion to a whole. A line chart is primarily used to show trends over time through connected data points rather than parts of a whole. A histogram serves to display the distribution of numerical data across specified intervals and is not focused on percentages but on frequency within each interval.