check the picture below.
[tex]\bf \textit{volume of a pyramid}\\\\
V=\cfrac{1}{3}Bh~~
\begin{cases}
B=area~of\\
\qquad its~base\\
h=height\\
------\\
B=\stackrel{16\times 16}{256}\\
h=15
\end{cases}\implies V=\cfrac{1}{3}(256)(15)\implies V=1280[/tex]
