Answer:
36 m³
Step-by-step explanation:
The volume of the pyramid can be calculated as

Where B is the area of the base and h is the height of the pyramid. In this case, the height of the pyramid is 9 m, so, we will need to replace h = 9 m
The base of the pyramid is a triangle, so the area of the base is

Then, replacing B = 12 and h = 9, we get that the volume of the pyramid is

Therefore, the volume is 36 m³