We are given:
V=lvh

Divide both sides by wh: \(\displaystyle\frac{{V}}{{w}}{h}={l}{w}\frac{{h}}{{w}}{h}\)

\(\displaystyle\frac{{V}}{{w}}{h}={l}\)

\(\displaystyle{l}=\frac{{V}}{{w}}{h}\)

Divide both sides by wh: \(\displaystyle\frac{{V}}{{w}}{h}={l}{w}\frac{{h}}{{w}}{h}\)

\(\displaystyle\frac{{V}}{{w}}{h}={l}\)

\(\displaystyle{l}=\frac{{V}}{{w}}{h}\)