Pie charts, also known as circle graphs, show values that are part of a larger whole, such as percentages. The graphs contain divisions called sectors, which divide the circle into portions that are proportional to the quantity each represents as part of the whole 360-degree circle.
Each sector becomes a piece of the pie. You get information and compare values by examining the pieces in relation to each other and to the whole pie. When a graphics-interpretation question provides you with a pie chart and designates the percentage values of each of its sectors, you can use it to figure out actual quantities.
The pie chart in the figure tells you that Plainfield has more Republican affiliates than Democrat and that Democrats constitute just over twice as many Plainfield residents as Independents do.