How are the three concepts of a city different? (City, Metro area, Urban places)
They are different in the size and the density of the agglomeration they refer to.
I think Wikipedia's definition on the city; metropolitan area and the urban area can help you understand the differences:
"A city is an urban area that is differentiated from a town, village, or hamlet by size, population density, importance, or legal status. In most parts of the world, cities are generally substantial and nearly always have an urban core, but in the United States many incorporated areas which have a very modest population, or a suburban or even mostly rural character, are designated as cities. City can also be a synonym for "downtown" or a "city centre".
A city usually consists of residential, industrial and business areas together with administrative functions which may relate to a wider geographical area. A large share of a city's area is primarily taken up by housing, which is then supported by infrastructure such as roads, streets and often public transport routes such as a rapid transit system. Lakes and rivers may be the only undeveloped areas within the city.
The difference between towns and cities is differently ...
The solution discussed the differences between the concepts of city, metropolitan and urban areas. The text contains 726 words.