# Pie Charts

A Pie chart is a circular diagram divided into sectors, with the size of each sector representing the magnitude of data it is depicting. Each sector of a pie chart can either be displayed in percentages (note all sectors must add up to 100%) or as an angle (note all sectors must add up to 360o).

Example

The table below lists some of the most popular football clubs and the number of students at a given institution that supports each. Use a Pie chart to represent the information given in the table.

 Football Clubs Number of Students Chelsea 50 Manchester United 200 Barcelona 350 Real Madrid 150 Inter Milan 25 Arsenal 100 Liverpool 40 AC Milan 75 The Pie Chart above depicts each sector as percentages. To calculate the percentages for each sector use the formula below:

% of a sector      =             Number of students                       x              100

Total number of students

So, to calculate the percentage of Chelsea fans:

% of Chelsea fans            =             50           x              100

990

% of Chelsea fans            =             5%

For Pie charts which depicts each sector as angles, the angles for each sector is found using the formula below:

Angle of a sector              =             Number of students                       x              360

Total number of students

So, to calculate the angle of the Chelsea sector:

Angle of Chelsea sector                                =             50           x              360

990

Angle of Chelsea sector                                =             18o

Note:    In most cases the questions set on Pie charts require those drawn depicting sectors in percentages.

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