The volume of a rectangular prism is given by the multiplication of its three dimensions: if [tex] w, h, l [/tex] are the width, height and length of the prism, the volume is
[tex] V = w\cdot h\cdot l [/tex]
So, in your case, you have
[tex] V = \dfrac{3}{8} \cdot \dfrac{5}{8} \cdot \dfrac{7}{8} = \dfrac{3\cdot 5 \cdot 7}{8\cdot 8 \cdot 8} = \dfrac{105}{512}[/tex]
