The Square Meter is an area measurement that corresponds to a square one meter long by one meter wide. Sometimes on the Internet, we can find questions like "One square meter equals how many meters?". Well, a common error in calculations involving areas is to treat this measure as a linear measure, but this is a quadratic measure, so a square with 5 m of side has an area of not 5 m², but 25 m². Unfortunately, for lack of knowledge, many people do not correctly distinguish these two concepts. This unit of measurement is widely used in measuring rooms, kitchens, bedrooms, etc. And for that reason it is common to see his appointment whenever we are dealing with the plan of an apartment or a house. This is a very important measure for the real estate market, since the value of real estate is often calculated, depending on the price of square meter, of the area where the property is.
The Square Kilometer is a unit of surface measure, which corresponds to the area of a square with a kilometer of side. This measure is equivalent to one million square meters, or even to one hundred hectares. In many of the medieval cities of Europe, the area that was protected by the walls that surrounded the city, was about one square kilometer. With an area of 59.1 km², Manhattan has a population of 1,640,000. This gives an average of 27,750 people/km², which makes it one of the most densely populated areas on the planet!