Answer:
9 inches.
Step-by-step explanation:
Fun question! The length of a space diagonal for a cube is [tex]\sqrt{3*sidelength^2}[/tex]
Thus, the first cube has a side diagonal of [tex]\sqrt{3}[/tex]
The next cube would have a side diagonal of 3
The third cube would have a side diagonal of [tex]3\sqrt{3}[/tex]
And the fourth cube would have a side diagonal of 9.
Since the fifth cube has a side length equal to the side diagonal of the fourth cube, it should be 9 inches.
