The volume of each box is:
[tex]V=\text{length}\cdot\text{width}\cdot\text{height}[/tex]Substituting with length = 9 in, width = 9 in, and height = 12 in, we get:
[tex]\begin{gathered} V=9\cdot9\cdot12 \\ V=972in^3 \end{gathered}[/tex]The volume of each notepad is:
[tex]V=\text{length}^3[/tex]Substituting with length = 3 in, we get:
[tex]\begin{gathered} V=3^3 \\ V=27in^3 \end{gathered}[/tex]The number of notepads that fit in 1 box is obtained dividing the volume of the box by the volume of each notepad, as follows:
[tex]\frac{972in^3}{27in^3}=36\text{ notepads}[/tex]