[tex]\textit{volume of a pyramid}\\\\ V=\cfrac{Bh}{3}~~ \begin{cases} B=\stackrel{base's}{area}\\ h=height\\[-0.5em] \hrulefill\\ B=\stackrel{11.3~\times~ 11.3}{127.69}\\ h=11.8 \end{cases}\implies \begin{array}{llll} V=\cfrac{(127.69)(11.8)}{3} \\\\\\ V\approx 502.2~m^3 \end{array}[/tex]