we know is a pyramid with a squarish base, and we know the base has a perimeter of 6.5 cm, meaning that each side in that square is 6.5 ÷ 4 = 1.625. Check the picture below.
[tex]\bf \textit{volume of a pyramid}\\\\ V=\cfrac{1}{3}Bh~~ \begin{cases} B=\stackrel{area~of}{its~base}\\ h=height\\[-0.5em] \hrulefill\\ B=\stackrel{1.625\times 1.625}{3.25}\\ h=3.2 \end{cases}\implies V=\cfrac{1}{3}(3.25)(3.2)\implies V=3.4\overline{6}[/tex]
