A rectangular steel plate with a length of 2.2 meters and a width of 1.5 meters has a mass of 514.8 kg. It is known that the mass per cubic meter of steel is 7.8 kg, and the thickness of this steel plate is very small

A rectangular steel plate with a length of 2.2 meters and a width of 1.5 meters has a mass of 514.8 kg. It is known that the mass per cubic meter of steel is 7.8 kg, and the thickness of this steel plate is very small

Volume = 514.8 △ 7.8 = 66m3
Height = 66 ﹣ 2.2 ﹣ 1.5 = 2m = 20m

A rectangular steel plate with a length of 2.2 meters and a width of 1.5 meters has a mass of 514.8 kg. It is known that the mass of steel per cubic decimeter is 7.8 kg. How much is the thickness of this steel plate?

The volume is:
514.8 △ 7.8 = 66 (cubic decimeter)
2.2 m = 22 decimeters
1.5m = 15m
The thickness of steel plate is
66÷（22×15）
=66÷330
=0.2 (decimeter)

A rectangular steel plate is 1.2 in length and 0.8 in width. How many square meters is the remaining steel plate area after cutting off a triangular steel plate 0.4 in height and 0.5 in width

1.2*0.8-0.4*0.5/2=0.86