10,000

One hectare is equivalent to 10,000 square meter. This is because prefix "hect" means 100, and squared 100 is 10,000.

The metric system of measure was first given a legal basis in 1795 by the French Revolutionary government. The law of 18 Germinal, Year III (7 April 1795) defined five units of measure:

The metre for length
The are (100 m2) for area [of land]
The st re (1 m3) for volume of firewood
The litre (1 dm3) for volumes of liquid
The gram for mass