Answer:
The required volume, if he wants to fill 75% of the pot's volume, is 11664cm³
Step-by-step explanation:
The volume of a pyramid is given as

Where V is the pot's volume, A is the base area and h is the height.
Our base is a square, so the base area, if s denotes the side length, would be s x s.
s = 36cm, therefore we have A = 36cm X 36cm = 1296cm².
The height is given as 36cm, therefore we have our volume to be:


Since Luis wants to fill 75% of the pot's volume with soil. Then it will take

Thus, the required volume, if he wants to fill 75% of the pot's volume, is 11664cm³