This problem is about volume.
Remember that volume can be found by the product of all three dimensions.
In this case, we have
[tex]l=\frac{1}{2}ft,w=\frac{1}{2}ft,h=\frac{3}{4}ft[/tex]So, the volume is
[tex]V=l\times w\times h=\frac{1}{2}\times\frac{1}{2}\times\frac{3}{4}=\frac{3}{16}ft^3[/tex]