A
The volume (V) of a pyramid is found using the formula
V = [tex]\frac{1}{3}[/tex] × area of base × height(h)
area of base = 9² = 81 ← area of a square, hence
324 = [tex]\frac{1}{3}[/tex] × 81 × h = 27h ( divide both sides by 27 )
h = [tex]\frac{324}{27}[/tex] = 12 → A
