Volume of a rectangular prism:
[tex]V=\text{Length}\times Width\times Height[/tex]Given prism:
[tex]V=\frac{2}{3}mm\times\frac{2}{3}\text{mm}\times1\frac{3}{4}mm[/tex]To multiply first write the mixed number as a improper fraction:
[tex]1\frac{3}{4}=1+\frac{3}{4}=\frac{4+3}{4}=\frac{7}{4}[/tex]The volume is:
[tex]\begin{gathered} V=\frac{2}{3}mm\times\frac{2}{3}\text{mm}\times\frac{7}{4}mm \\ \\ V=\frac{2\times2\times7}{3\times3\times4}mm^3 \\ \\ V=\frac{28}{36}mm^3 \\ \\ V=\frac{7}{9}mm^3 \end{gathered}[/tex]