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Unlock This CourseEvery country's economy is made up of different types of jobs and industries. Geographers group these into three main sectors based on what people do for work. Understanding these sectors helps us see how developed a country is and how its economy is changing over time.
Key Definitions:
Farmers growing wheat, miners digging for coal, fishermen catching fish, loggers cutting down trees and oil workers drilling for petroleum. These jobs are often found in rural areas and provide the basic materials that other industries need.
Car factories assembling vehicles, bakeries making bread from flour, textile mills weaving cloth, steel works producing metal and construction workers building houses. These jobs transform raw materials into finished products.
Triangular graphs are special charts that show three pieces of information at the same time. They're perfect for displaying employment structure because they can show the percentage of people working in primary, secondary and tertiary sectors all on one graph. The clever thing about triangular graphs is that the three percentages always add up to 100%.
Imagine an equilateral triangle (all sides the same length). Each side represents one of the three economic sectors. The triangle is divided into a grid and each point inside the triangle represents a country or region. The position of the point tells us the employment structure of that place.
Each side of the triangle has a scale from 0% to 100%. The bottom-left side shows primary sector percentages, the bottom-right shows secondary and the left side shows tertiary sector percentages.
To plot a country, you need three percentages that add up to 100%. Find where these three values meet inside the triangle - that's where you place your point.
Countries in different parts of the triangle show different levels of development. More developed countries tend to cluster in certain areas of the triangle.
Drawing and using triangular graphs might seem tricky at first, but once you understand the method, it becomes much easier. Here's how to do it properly:
Start by drawing an equilateral triangle using a ruler and compass, or use graph paper. Each side should be the same length - about 10cm works well. Label each side clearly: Primary (bottom), Secondary (right) and Tertiary (left). Add percentage scales from 0% to 100% along each side.
Always use a sharp pencil and ruler when drawing triangular graphs. Accuracy is crucial because small errors can make your data points appear in the wrong place, leading to incorrect conclusions about development levels.
To plot a country's employment structure, you need to find where three percentage values intersect. For example, if a country has 20% primary, 30% secondary and 50% tertiary employment:
Countries like the UK, Germany and Japan typically appear in the upper part of the triangle. They have high tertiary sector employment (60-80%), moderate secondary (20-35%) and very low primary (1-10%).
Countries like Bangladesh, Ethiopia and rural parts of India appear towards the bottom-left. They have high primary sector employment (40-80%), lower secondary (10-25%) and growing tertiary sectors.
Once you've plotted countries on a triangular graph, you can spot patterns that reveal important information about economic development and how countries are changing over time.
The position of countries on triangular graphs shows clear development patterns. As countries develop economically, they tend to move in a predictable direction across the triangle - from high primary employment towards high tertiary employment.
In 1800, the UK had about 75% primary, 20% secondary and 5% tertiary employment. By 1900, this had shifted to 15% primary, 50% secondary and 35% tertiary. Today, it's approximately 2% primary, 18% secondary and 80% tertiary. On a triangular graph, you'd see the UK's position moving from bottom-left to top-centre over time.
Triangular graphs make it easy to compare different countries' economic structures at a glance. Countries at similar development levels cluster together, whilst those at different stages spread across the triangle.
Bottom-left area: High primary sector employment, typical of least developed countries where most people work in farming.
Bottom-right area: High secondary sector employment, typical of newly industrialised countries with lots of manufacturing.
Top area: High tertiary sector employment, typical of highly developed countries with service-based economies.
When drawing and interpreting triangular graphs, students often make similar mistakes. Being aware of these helps you avoid them and improves your accuracy.
The most common mistake is plotting points incorrectly. Always double-check that your three percentages add up to 100% before plotting. Use a ruler to draw accurate parallel lines when finding intersection points.
Make sure you're reading the correct scale for each axis. Each side of the triangle represents a different sector and it's easy to mix them up. Always label your axes clearly.
The best way to master triangular graphs is through practice. Start with simple data sets and gradually work up to more complex comparisons. Try plotting the same country at different time periods to see how its economy has changed.
In exams, you might be asked to plot data points, read values from existing points, or describe patterns. Always show your working clearly, use a ruler for accuracy and explain what the patterns tell us about economic development.
Triangular graphs aren't just useful for geography exams - they're used by economists, governments and international organisations to understand and compare economic development around the world.
Governments use employment structure data to plan their economic development. If a country has too many people in primary sector jobs, they might invest in education and infrastructure to help people move into secondary and tertiary jobs.
China's rapid development since 1980 shows clearly on triangular graphs. In 1980, about 69% of Chinese workers were in primary sector jobs. By 2020, this had fallen to just 25%, whilst tertiary sector employment rose from 12% to 48%. This shift represents one of the fastest economic transformations in history.