calculate weight of steel plate

Weight = Volume * Density

Weight = length*breadth*thickness* Density

length =12000 mm = 12 m

breadth =4390 mm = 4.39 m

thickness = 20 mm = 0.02 m

Density of steel = 7850 kg/m^3 

[ Different steels have different Densities ] 

Weight = 12 * 4.39 * 0.02 *7850 kg 

[m^3 * kg/m^3 =kg ]

Weight = 8270.76 kg. is the weight of the steel sheet