Chapter 1 - Problem Solving and Critical Thinking - 1.2 Estimation, Graphs, and Mathematical Models - Exercise Set 1.2 - Page 28: 58

A circle graph is a graphic plot which gives us valuable information and data in a proportional manner. A complete circle is considered as 100 % or as 1. Any information when depicted using a circle, it divides the circle into different proportions, and these proportions are fraction of 100 % or 1.

For example