Final answer:
The volume of the rectangular pyramid is 594 km³.
Step-by-step explanation:
The volume of a rectangular pyramid can be calculated by multiplying the base area by the height. In this case, the base of the pyramid is a rectangle with dimensions 6 km and 11 km, so the base area is (6 km)(11 km) = 66 km². The height of the pyramid is given as 9 km. Therefore, the volume of the pyramid is (66 km²)(9 km) = 594 km³.