If the prisms are identical, the we know the missing length of the prism on the left is 10 m. To find the volume of one of the prisms, we can do length times width times depth.
So one prism has a volume of 5 * 10 * 11 = 550
We have two identical prisms, so the total volume is double the volume of one prism.
The answer is 1100 cubic meters