The Rank Size Rule notes the relationship between the ranks of cities and their populations.
It was advanced by Zipf in 1941
The formula is where is the population of towns ranked , is the population of the largest town and is the rank of the town.
For example, if the largest town has a population of , the second largest town will have a population of , the 3rd largest will have a population of and so on.
The Law of the Primate City
The primate city is the largest most dominant city in a region.
The degree of primacy refers to the dominance of the largest city over the rest of the country.
Most LDCs (Less Developed Countries) have a high degree of primacy while most MDCs (More Developed Countries) have a low degree of primacy.
where 
is the population of towns ranked 
, 
is the population of the largest town and 
, the second largest town will have a population of 
, the 3rd largest will have a population of 
and so on.
