Pie Chart

The “pie chart” also is known as “circle chart” divides the circular statistical graphic into sectors or slices in order to illustrate the numerical problems. Each sector denotes a proportionate part of the whole. To find out the composition of something, Pie-chart works the best at that time. In most of the cases, pie charts replace some other graphs like the bar graph, line plots, histograms etc.

Pie Chart Formula

The pie chart is an important type of data representation. It contains different segments and sectors in which each segment and sectors of a pie chart forms a certain portion of the total(percentage). The total of all the data is equal to 360°.

The total value of the pie is always 100%.

To work out with the percentage for a pie chart, follow the steps given below:

  • Categorize the data
  • Calculate the total
  • Divide the categories
  • Convert into percentages
  • Finally, calculate the degrees

Therefore, the pie chart formula is given as

(Given Data/Total value of Data) × 360°

Pie Chart Example

Imagine a teacher surveys her class on the basis of their favourite Sports:

Football Hockey Cricket Basketball Badminton
10 5 5 10 10

The data above can be represented by a pie-chart as following and by using the circle graph formula i.e. the pie chart formula given below. It makes the size of portion easy to understand.

Step 1: First, Enter the data into the table.

Football Hockey Cricket Basketball Badminton
10 5 5 10 10

Step 2: Add all the values in the table to get the total.

I.e Total students are 40 in this case.

Step 3: Next, divide each value by the total and multiply by 100 to get a per cent:

Football                                 Hockey                        Cricket                   Basketball          Badminton
(10/40) × 100

=25%

(5/ 40) × 100

=12.5%

(5/40) ×100

=12.5%

(10/ 40) ×100

=25%

(10/40)× 100

=25%

Step 4: Next to know how many degrees for each “pie sector” we need, we will take a full circle of 360° and follow the calculations below:

The central angle of each component = (Value of each component/sum of values of all the components)✕360°

Football Hockey Cricket Basketball Badminton
(10/ 40)× 360°

=90°

(5 / 40) × 360°

=45°

(5/40) × 360°

=45°

(10/ 40)× 360°

=90°

(10/ 40) × 360°

=90°

Now you can draw a pie chart.

Step 5: Draw a circle and use the protractor to measure the degree of each sector.

Pie Chart Example

Uses of Pie Chart

Within a business, it is used to compare areas of growth such as turnover, profit, and exposure.
To represent categorical data.

Pie Chart Diagram

Advantages of a Pie Chart

  • The picture is simple and easy-to-understand
  • Data can be represented visually as a fractional part of a whole
  • It helps in providing an effective communication tool for the even uninformed audience
  • Provides a data comparison for the audience at a glance to give an immediate analysis or to quickly understand information
  • No need for readers to examine or measure underlying numbers themselves which can be removed by using this chart
  • To emphasize a few points you want to make, you can manipulate pieces of data in the pie chart

Disadvantages of a Pie Chart

  • It becomes less effective, If there are too many pieces of data to use
  • If there are too many pieces of data, and even if you add data labels and numbers may not help here, they themselves may become crowded and hard to read
  • As this chart only represents one data set, You need a series to compare multiple sets
  • This may make it more difficult for readers when it comes to analyze and assimilate information quickly

You can practice another pie chart question for class 8 given below:

Pie Chart Question

Question: Priya lists down her monthly expenditure as follows:

Expenditure Amount
Rent 4000
Food 5400
Clothing 2800
Savings 400

Draw a pie chart for her monthly expenses.

You might also like to practice some more Mathematical topics. Download BYJU’S- The Learning App for a variety of topics and concepts to learn from.

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