Pie charts show how much each category represents as a proportion of the WHOLE, by using a circular format with different-sized “slices” for different percentages of the whole.
The bar/column chart excels at showing discrete data while comparing one data-point vs. another, while the pie chart is the classic way to show how various parts makes up a whole.
Both make it easy to for readers compare values relative to each other
Bar graphs USE a SERIES of rectangular bars to show absolute values or proportions for each of the CATEGORIES