Pie Charts Examples, Questions and Solutions

Pie Chart Examples - Page - 5
Pie Chart Questions - Page - 6
Pie Chart Video Tutorial - Page - 7

Pie charts are a typical type of data representation where data is represented as a part of a circle. The circle represents the total value (or 100%), and the different parts represent certain proportions (or percentage) of the total. In a pie chart, the are length of each sector (and in turn its central angle and area), is proportional to the part it represents.
The origin of the pie chart is traced back to Florence Nightingale in 1858. This was the year when she presented a paper on the causes of deaths in her army in the eastern part of the world.
Following is the pie chart originally developed by Florence Nightingale in the year 1858. (Actually called by her as the ‘Polar Area Diagram’.)

The below graphic gives the number of deaths that occurred from the diseases that could have been prevented (in light grey), those that were the results of wounds (in dark, grey) and those due to other causes (in black).

There are two approaches to constructing a pie chart from any given data.

A) Degree Approach: The central angle in a circle represents  360^{\circ} , so any part or segment in pie chart is calculated as a proportion of  360^{\circ}.
B) Percentage Approach: In this case, any part or segment in a pie chart is calculated as a part of 100%.

If we convert the same pie chart into the degree format, we will be required to do the following conversions:

Total = 100 = 360^{\circ}
Hence = 1% = 3.6^{\circ}
Center = 10% = 36^{\circ}
North = 20% = 72^{\circ}
South = 25% = 90^{\circ}
East = 15% = 54^{\circ}
West = 30% = 108^{\circ}


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