Recall that the volume of a squared base cuboid is:

where l is the length of the squared base, and h is the height of the cuboid.
Substituting V=675 cm³ and h=3cm we get:

Dividing the above result by 3cm we get:

Therefore:
![\begin{gathered} l=\sqrt[]{225cm^2}, \\ l=15cm\text{.} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/k31awg0d98ovcdy6413nya9mwn85atxw0e.png)
Answer: The length is 15cm.