Proportional area chart used almost exclusively in showing relative sizes of the components of a data-set, in comparison to one another and to the whole set. It consists of a circle (disc) divided into several (usually not exceeding six) segments. Area of each segment (called slice or wedge) is of the same percentage of the circle as the component it represents is of the whole data set. Most important segment is commonly shown in the '12 o'clock' position with each successive less important segment following in a clockwise direction. Also called circle diagram, circle graph, pizza chart, or sector graph.