#### Answer

720$mm^{3}$

#### Work Step by Step

To find the volume of a triangular prism, we simply use the formula V=$\frac{1}{2}$bhl, where b is the base, h is the height,and l is the length.
We plug in the values for base, height, and length:
V=$\frac{1}{2}$(12mm)(20mm)(6mm)
We multiply to find the volume:
V=720$mm^{2}$