Square kilometer: Square kilometer (symbol is km2) is the metric unit of area, which is defined as "the area of a square with a side length of 1km".
1 hectare = 1 10,000 square meters.
Hectares: The unit symbol of a hectare is "hm2", where hm stands for 100m and h stands for the square of 100m, that is, 10000 m2, that is, 1 hectare.
1 m2 = 100 square decimeter.
Square meter: It is the metric unit of area. It is defined as the area of a square with a side length of 1 m.
1 square decimeter = 100 square centimeter.
Square decimeter: defined as "the area of a square with a side length of 1 decimeter".
1 cm2 = 100 mm2.
With point d as DE¡ÍAB in e,
And DC¡ÍCB, AB¡ÍCB,
¡à¡ÏDEB=¡ÏABC=¡ÏDCB=90£¬
¡à Quadrilateral DEBC is a rectangle,
In Rt¡÷ADE, ¡Ï ¦Á = 43, DE = CB =139m.