In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data
v = 1/3 * b * h
h = ?
Step 02:
[tex]\begin{gathered} v=\frac{1}{3}\cdot b\cdot h \\ 3v\text{ = b}\cdot h \\ \frac{3v}{b}=h \end{gathered}[/tex]The answer is:
h = 3v / b