A rectangular pyramid has a base with dimensions 5 inches by 7 inches. The height of the pyramid is unknown. If the volume of the pyramid is 105 cubic inches, what is the height of the pyramid? Explain the steps

bearing in mind that the volume of a pyramid is the product of the area of its base and its height, now, this one has a rectangular base of 5x7, so its base area is 35.
[tex] \bf \textit{volume of a pyramid}\\\\
V=\cfrac{1}{3}Bh~~
\begin{cases}
B=area~of\\
\qquad its~base\\
h=height\\
------\\
V=\stackrel{in^3}{105}\\
B=\stackrel{5\times 7}{35}
\end{cases}\implies 105=\cfrac{1}{3}(35)h
\\\\\\
3(105)=35h\implies 315=35h\implies \cfrac{315}{35}=h\implies 9=h [/tex]