440 g
First, determine the volume of each sheet. And it's easier if each dimension is using the same unit of measure. So each sheet is 28 cm by 22 cm by 0.30 cm. Multiply them together
28 cm * 22 cm * 0.30 cm= 184.8 cm^3
Since we have 2 identical sheets, double the total volume
184.8 cm^3 * 2 = 369.6 cm^3
Now multiple the volume by the density
369.6 cm^3 * 1.2 g/cm^3 = 443.52 g
Round the results to 2 significant digits since all of the given figures are only 2 significant digits long.
443.52 g = 440 g