In graph theory, a circle graph is the intersection graph of a set of chords of a circle. It is an undirected graph whose vertices can be associated with chords of a circle such that two vertices are adjacent if and only if the corresponding chords cross each other. The circle graph is also called pi graph and pi chart.
Some important formulas of circle graph are given below:
1. Percentages = (Amount in the Category ⁄ Total) × 100
2. Angle = (Amount in the Category ⁄ Total) × 360°
Example 1: A fruit basket is filled with 36% Apples, 29% Bananas, 9% Mangoes, 7% Pineapples and 19% Grapes. Prepare a circle graph chart as per the data provided.
Example 2: The following data gives the information about the number of different mobile phones used by the employees of one department in a company. Draw the circle chart for the following data using angle proportions.
|Mobile phone||Number of users|
Solution: Angle = (Amount in the Category ⁄ Total) × 360°
|Mobile phone||Number of users||Angle|
|Apple phone||9||(9/36) × 360° = 90°|
|HTC||12||(12/36) × 360° = 120°|
|Samsung||6||(6/36) × 360° = 60°|
|Sony||8||(8/36) × 360° = 80°|
|Nokia||1||(1/36) × 360° = 10°|
Example 3: The below table shows the percentage of expenses of a person in a month. Draw a circle chart for the data given.
|Category||Percentage of expense|
Food = 37%
Rent = 16%
Clothing = 11%
Education = 20%
Medicine = 4%
Other expenses = 12%