According to the dimensions of the box, the row already fit the width and the height of the box. But it does not with the length.
The length of each prism is 7.5cm, so this is the length of the rows.
Since the length of the box is 22.5cm, 3 rows of prism will fit in the box:
[tex]\frac{22.5}{7.5}=3[/tex]
Each row has 9 prisms, it means that in total, each box can fit 27 prisms.
