Database results:
examBoard: Cambridge
examType: IGCSE
lessonTitle: Proportion, Ratio and Frequency
Geography isn't just about maps and places - it's also about understanding numerical patterns and relationships in our world. Mathematical skills help geographers make sense of complex data and identify important trends that shape our environment and societies.
Key Definitions:
These mathematical skills are essential tools for geographers because they allow us to:
You'll apply these skills when:
Proportion is about understanding parts in relation to the whole. In geography, we often express proportions as percentages, which makes comparing different datasets much easier.
To calculate a proportion, divide the part by the whole, then multiply by 100 to get a percentage:
Proportion (%) = (Part ÷ Whole) × 100
Example: If a city has 250,000 residents and 45,000 are under 18 years old, what proportion of the population is under 18?
Proportion = (45,000 ÷ 250,000) × 100 = 18%
So 18% of the city's population is under 18 years old.
Proportions are used extensively in geography to understand:
What proportion of a country is forested, urban, or agricultural? For example, about 13% of the UK's land area is covered by woodland, compared to 31% of France.
What proportion of people live in urban vs rural areas? Globally, 56% of people live in urban areas, but this varies widely by country.
What proportion of energy comes from renewable sources? In the UK, about 43% of electricity generation came from renewable sources in 2020.
While proportions compare a part to the whole, ratios compare one quantity directly to another. Ratios are typically written with a colon (e.g., 3:1) or as a fraction (e.g., 3/1).
Ratios help us understand relationships between different geographical variables and make direct comparisons between places or time periods.
Example: If a country has 12 million working-age people (15-64) and 8 million dependents (under 15 or over 64), what is the dependency ratio?
Dependency ratio = Number of dependents : Number of working-age people
Dependency ratio = 8 million : 12 million = 2:3 (simplified from 8:12)
This means for every 3 working-age people, there are 2 dependents.
Frequency refers to how often something occurs within a dataset. Understanding frequency helps geographers identify patterns and trends in data.
A frequency distribution shows how often different values occur in a dataset. This can be displayed in tables or graphs.
To create a frequency table:
Example: Annual rainfall measurements from a weather station
| Rainfall (mm) | Frequency | Percentage |
|---|---|---|
| 0-25 | 8 | 22% |
| 26-50 | 15 | 41% |
| 51-75 | 10 | 27% |
| 76-100 | 4 | 10% |
When analyzing frequency data, look for:
From our rainfall example, we can see that:
Population pyramids are perfect examples of how proportion, ratio and frequency are used in geography. These graphs show the age and sex structure of a population, with:
By comparing population pyramids from different countries or time periods, geographers can identify important demographic trends like aging populations, high birth rates, or the impacts of historical events like wars or economic booms.
Development indicators are measurements that help us compare the level of development between countries. Many of these rely on proportions, ratios and frequency analysis.
Literacy rate: The proportion of people who can read and write (e.g., UK: 99%, Niger: 35%)
School enrollment ratio: The proportion of children attending school
Employment by sector: The proportion of workers in primary, secondary and tertiary industries
Income inequality ratio: How much the richest earn compared to the poorest
Infant mortality rate: Deaths per 1,000 live births
Access to healthcare: Proportion of population with healthcare access
When tackling questions involving proportion, ratio and frequency in your iGCSE Geography exam:
Proportion: Part compared to whole (usually as a percentage)
Ratio: Direct comparison between two quantities (e.g., 3:1)
Frequency: How often values occur in a dataset
Remember that these skills help you analyze geographical data more effectively and communicate your findings clearly. Practice applying these skills to different geographical contexts to build your confidence for the exam.
Log in to track your progress and mark lessons as complete!
Login NowDon't have an account? Sign up here.