actually, the "slant height" is 4, but the vertical height or "altitude" of the equilateral triangle is not 4
but anyway.....[tex]\bf \begin{array}{cllll}
\textit{height of an equilateral triangle}\\\\
h=\cfrac{s\sqrt{3}}{2}\\
----------\\
\textit{area of an equilateral triangle}\\\\
A=\cfrac{s^2\sqrt{3}}{4}
\end{array}\qquad s=\textit{length of one side}[/tex]
and the volume, is the area of the triangle, times the length, so, whatever you get for the area of the triangle * 10
