Area conversion:
1 cm2 = 100 mm2 =0. 1550 in2.
1 square meter = 10000 square centimeter = 1. 1960 square yard.
1 hectare =15mu =10000m2.
1 mu = 666.67m2.
1 ha =10000m2 = 2.445438+0 1 mu.
1 square kilometer = 100 hectare = 0.385438+0 square mile.
Extended data
The area of a circle—
In the 5th century BC, Hippocrates in Hiosburg was the first person to show that the area of a disk (the area surrounded by a circle) was directly proportional to the square of its diameter, which was part of his orthogonality in Hippocrates' time, but the proportionality constant was not determined. In the 5th century BC, eudoxus of Cornydos also found that the area of a disk is directly proportional to the square of its radius.
Mathematician Archimedes used the tools of Euclidean geometry to show that in his book Measuring a Circle, the area inside a circle is the same as that of a right triangle, and its diameter triangle has the circumference of a circle and its height is equal to the radius of the circle. The perimeter is 2πr, the area of the triangle is half of the reference times the height, and the area is πr? .