The pie chart represents data in a circular graph. The pieces of the chart or graph show the data size. The various components are represented by the pieces of a circle and the whole circle is the sum of the values of all components. One can get the pie chart definition, formula, use, solved examples, and steps to create a pie chart in the below sections.
Pie Chart Definition
A pie chart is also a graph and is a type of pictorial representation of data. It divides the circle into various sectors in order to explain the numeric values. Each section is a proportionate part of the whole circle. We use a pie chart to find the composition of something. The pie chart is also known as the circle chart.
A pie chart is used for data representation. The total of all data in a pie is equal to 360° and the total value of a pie is always 100%.
The central angle for a component formula is given as
Central angle for a component = (Value of the component / Sum of the values of all components) * 360°
Steps to Make a Pie Chart
Follow the below-mentioned steps to create a pie chart/ circle chart for the given data.
- Enter the given data into a table to make the process easy for you.
- Find the sum of values in the table.
- Divide each value in the table by sum and multiply the result with 100 to get the percent.
- To get the degrees of each value, substitute the values in the formula i.e (Value of each component/sum) * 360A pie chart is used for the data representation. The total of all data in a pie is equal to 360° and the total value of a pie is always 100%.
- The central angle for a component formula is given as Central angle for a component = (Value of the component / Sum of the values of all components) * 360°.
- Draw a circle and use a protractor to measure the degree of each sector.
Advantages and Disadvantages of Pie Chart
Advantages
- It is simple and easy to understand
- Data can be represented visually as a fractional part of the whole.
- It helps in providing an effective communication tool for the uninformed audience.
Disadvantages
- It can represent only one set of data. So, you need a series to compare multiple sets.
- If you have too many pieces of data, and even you add labels and numbers may not help here, they themselves may become crowded and hard to read.
Example Questions & Answers
Example 1.
The following table shows the expenditure in percentage incurred on the construction of a house in a city:
| Item | Brick | Cement | Steel | Labour | Miscellaneous |
|---|---|---|---|---|---|
| Expenditure (in percentage) | 18% | 30% | 10% | 12% | 30% |
Draw a pie chart for the above data.
Solution:
Total percentage = 100
Central angle for a component = (Value of the component / Sum of the values of all components) * 360°
Calculation of central angles:
| Item | Expenditure (in percentage) | Central Angle |
|---|---|---|
| Brick | 18% | ((18 / 100) * 360°) = 64.8° |
| Cement | 30% | ((30 / 100) * 360°) = 108° |
| Steel | 10% | ((10 / 100) * 360°) = 36° |
| Labour | 12% | ((12 / 100) * 360° = 43.2° |
| Miscellaneous | 30% | ((30 / 100) * 360°) = 108° |
Construction for creating a pie chart
Steps of construction:
1. Draw a circle of any convenient radius.
2. Draw a horizontal radius of the circle.
3. Draw sectors starting from the horizontal radius with central angles of 64.8°, 108°, 36°, 43.2°, and 108° respectively.
4. Shade the sectors differently using different colors and label them.
Thus, we obtain the required pie chart, shown in the above figure.
Example 2.
The marks scored by a student in his examination are shown below:
| Subject | English | Hindi | Maths | Science | Social |
|---|---|---|---|---|---|
| Marks | 70 | 85 | 76 | 88 | 92 |
Draw a pie chart for the above data.
Solution:
The given table contains the marks of a student in an exam.
The total marks scored by a student = 411
Central angle for a component = (Each subject marks / total marks) * 360°
Calculation of central angles:
| Subject | Marks | Central Angle |
|---|---|---|
| English | 70 | (70 / 411) * 360° = 61.31° |
| Hindi | 85 | (85 / 411) * 360° = 74.45° |
| Maths | 76 | (76 / 411) * 360° = 66.56° |
| Science | 88 | (88 / 411) * 360° = 77.08° |
| Social | 92 | (92 / 411) * 360° = 80.58° |
Construction for creating a pie chart
Steps of construction:
1. Draw a circle.
2. Draw sectors starting from the horizontal radius with central angles of 61.31°, 74.45°, 66.56°, 77.08°, 80.58° respectively.
3. Shade the sectors differently using different colors and label them.
Thus, we obtain the required pie chart, shown in the above figure.
Example 3.
The data on the mode of transport used by 1000 students are given below:
| Mode of Transport | Bus | Cycle | Train | Car | Scooter |
|---|---|---|---|---|---|
| Number of Students | 150 | 50 | 200 | 100 | 500 |
Represent the data on a pie chart.
Solution:
The given table shows the mode of transport used by 1000 students to reach the school.
Total Number of Students = 1000
Central angle for a component = (Value of the component / Sum of the values of all components) * 360°
Calculation of central angles:
| Mode of Transport | Number of Students | Central Angle |
|---|---|---|
| Bus | 150 | (150 / 1000) * 360 = 54° |
| Cycle | 50 | (50 / 1000) * 360 = 18° |
| Train | 200 | (200 / 1000) * 360 = 72° |
| Car | 100 | (100 / 1000) * 360 = 36° |
| Scooter | 500 | (500 / 1000) * 360 = 180° |
Construction for creating a pie chart
1. Draw a circle of any convenient radius.
2. Draw a horizontal radius of the circle.
3. Draw sectors starting from the horizontal radius with central angles of 54°, 18°, 72°, 36°, and 180°.
4. Shade the sectors differently using different colors and label them.
Thus, we obtain the required pie chart, shown in the above figure.
FAQs on Pie Chart
1. What are the uses of a pie chart?
A pie chart is used to represent categorical data, to compare areas of growth in a business like turnover profit and exposure.
2. What are the pie chart examples?
The real-life examples of the pie charts are a representation of kinds of cars sold in a month, types of food items liked by people in a room, marks scored by students in a class, etc
3. What is the formula to calculate the percentage of each component of a pie chart?
The pie chart formula to calculate the central angle for a component is as follows:
Central angle for a component = (Value of the component / Sum of the values of all components) * 360°