pie chart and its uses

PIE CHARTS (OR GRAPHS) AND ITS USES IN ECONOMIC what is a pie chart:

A pie chart or graph is a simple circle of any convenient size which is divided into sections or sectors, each of which is proportional to the quantity or value it represents.

other economic tools and table

ff

HOW IS A PIE CHART MEASURED?

The pie chart is usually measured either in percentage or in degrees with the aid of a mathematical device called a protractor.

The entire circle is represented by 360^o or 100% and each sector is measured in degrees with the aid of a protractor.

h

1. 1. public enterprises
   2. private enterprises
   3. limited liability companies
   4. migration

   
   4. ORGANIC MANURING
   5. FARM YARD MANURE

Methods of Constructing a pie chart

Add up the total figure of the product or value under consideration.

Work out the percentage or degree of the total which each component part represents.

Draw a circle of a convenient size.

 Divide the circle up into sectors suspended by these angles calculated in step (ii) above using a protractor.

Write the percentage or degree of each sector by it.

Use a key where the information cannot be written inside the circle to show what each sector represents.

HOW TO USE A PIE CHART TO SOLVE ECONOMIC DATA REPRESENTATION

Example 1 of the proper use of the pie chart

Represent the information I table by means of a piechart, the value of the most important exports of Nigeria in 1980, both in percentages and in degrees.

Value of the most important exports in Nigeria in 1980.

Export product	Value in millions
Cocoa	200
Groundnut	140
Petroleum	240
Coal	50
Others	90

Solution

• Add up the total value of all the products, i.e. 200 + 140 + 240 + 50 + 90 = 720.
• Arrange your workings or calculations as follows:

Export Product	Value in Millions (N)	Workings in percentage (%)	Workings in degree (0o) Angle of sector
Cocoa	20	200
Groundnut	140
Petroleum	240
Coal	50
Others	90
TOTAL	720

 Using the values in degree, i.e. 100%, 70^o, 120^o, 25^o and 45^o, a pie chart in Fig. 2.2 is now drawn using a protractor.

Pie chart showing value of the most important exports of Nigeria in 1980.

Example 2

The table below shows the sectoral allocation of a country’s budget. Illustrate the data accurately with a pi chart. Show your workings clearly.

Table 2.4: Sectoral allocation of a country’s budget.

Sector                                     Amount (N Million)

Health                                     30

Education                    25

Housing                       15

Manufacturing            10ul

Agriculture                  20

Solution

Sector	Amount (N Million) (Angle of Sector)	Workings in degrees
Health	30
Education	25
Housing	15
Manufacturing	10
Agriculture	20

Total                100                  360^o

• Add up the total value of all the sectors, i.e. 30 + 25 + 15 + 10 + 20 = 100
• Arrange your workings or calculations in the following manner only in degrees.
• Using the values in degrees, i.e. 108^o, 90^o, 54^o, 36^o and 72^o, a pie chart is now drawn.