If we split this shape into 2 rectangles, we have 2 rectangles that each measure 10m x 20m x 200cm. 200 cm = 2 m. Volume is found by multiplying length times width times height. We have 2 shapes so we will have 2 volumes that we will add together to get a total volume. 10*20*2=400 m cubed. Two of those is 800 m cubed.