# Construction of Pie Chart

Now we will discuss about the construction of pie chart or pie graph. In brief let us recall about, what is a pie chart?

It is a circular graph which is used to represent data. In this :

Various observations of the data are represented by the sectors of the circle.

The total angle formed at the centre is 360°.

The whole circle represents the sum of the values of all the components.

The angle at the centre corresponding to the particular observation component is given by

If the values of observation/components are expressed in percentage, then the centre angle corresponding to particular observation/component is given by

How to construct a pie chart?

Steps of construction of pie chart for a given data:

Find the central angle for each component using the formula given on the previous page.

Draw a circle of any radius.

Draw a horizontal radius

Starting with the horizontal radius, draw radii, making central angles corresponding to the values of respective components.

Repeat the process for all the components of the given data.

These radii divide the whole circle into various sectors.

Now, shade the sectors with different colours to denote various components.

Thus, we obtain the required pie chart.

Solved example on

construction of pie chart/pie graph:

1. The following table shows the numbers of hours spent by a child on different events on a working day.

Represent the adjoining information on a pie chart

 Activity No. of Hours School 6 Sleep 8 Playing 2 Study 4 T. V. 1 Others 3

The central angles for various observations can be calculated as:

 Activity No. of Hours Measure of central angle School 6 (6/24 × 360)° = 90° Sleep 8 (8/24 × 360)° = 120° Playing 2 (2/24 × 360)° = 30° Study 4 (4/24 × 360)° = 60° T. V. 1 (1/24 × 360)° = 15° Others 3 (3/24 × 360)° = 45°



Now, we shall represent these angles within the circle as different sectors. Then we now make the pie chart:

2. The favourite flavours of ice-cream for the children in a locality are given in percentage as follow. Draw the pie chart to represent the given information

 Flavours % of Students Prefer the Flavours Vanilla 25 % Strawberry 15 % Chocolate 10 % Kesar-Pista 30 % Mango Zap 20 %

The central angles for various observations can be calculated as:

 Flavours % of Students Prefer the Flavours Measure of Central Angles Vanilla 25 % (25/100 × 360)° = 90° Strawberry 15 % (15/100 × 360)° = 54° Chocolate 10 % (10/100 × 360)° = 36° Kesar-Pista 30 % (30/100 × 360)° = 108° Mango Zap 20 % (20/100 × 360)° = 72°

Now, we shall represent these angles within a circle to obtain the required pie graph.

Statistics

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