The formula for volume of a pyramid is:
\(V = \frac{1}{3}BH\)
Where B is the area of the base and H is the height.
The base is just a square with side length 723 ft, so the area of the base is just 7232 = 522,729 sq. ft.
The height is 341 ft.
B = 522,729
H = 341
Literally just plug this into the formula to get the answer.