PIE CHARTS (OR GRAPHS) AND ITS USES IN ECONOMIC ACTIVITIES
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
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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.
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 public enterprises
 private enterprises
 limited liability companies
 migration
 population
 market concept
 money market
 shares
 how companies raises funds for expansion
1. ENVIRONMENTAL FACTORS AFFECTING AGRICULTURAL PRODUCTION
2. DISEASES
3. 52. SOIL MICROORGANISMS
4. ORGANIC MANURING
5. FARM YARD MANURE
6. HUMUS
7. COMPOST
8. CROP ROTATION
9. GRAZING AND OVER GRAZING
10. IRRIGATION AND DRAINAGE
Methods of constructing a pie chart
 Add up the total figure of the product or value under consideration.
 Work out the percentage or degree the total which each component part represents.
 Draw a circle of a convenient size.
 Divide the circle up into sector suspended by these angles calculated in step (ii) above using a protractor.
 Write the percentage or degree of each sector by it.
 Use key where the information cannot be written inside the circle to show what each sector represents.
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HOW TO USE A PIE CHART TO SOLVE ECONOMIC DATA REPRESENTATION
Example 1 of the proper use the pie chart
Represent the information I table by means of pie chart, the value of the most important exports of Nigeria in 1980, both in percentages and in degrees.
Table 2.3: Value of the most important exports on 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 (  Workings in percentage (%)  Workings in degree (0^{o}) 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 pie 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 10
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.