Let the length of one side of the base square be a cm.
The Volume of a pyramid is [tex] \frac{1}{3}*area_b_a_s_e *height[/tex]
the area of the base is a^2,
we apply the formula
[tex]256= \frac{1}{3}*a^{2}*12 [/tex]
[tex]256= 4a^{2} [/tex]
[tex]256= (2a)^{2} [/tex]
[tex]2a= \sqrt{256}=16[/tex]
a=8 (cm)
Answer: 8 cm
