Answer:
2.65 inches
Explanation:
The length of the toothpick is 3 inches.
The of the base of the box is 1 inch x 1 inch.
Let the height of the box is h inch, so, the dimension of the box is
1 inch x 1 inch x h inch.
The toothpick must be placed diagonally for the minimum height of the box, as shown in the figure,
So, the length of the longest diagonal of the box
![d=\sqrt {1^2+1^2+h^2}](https://img.qammunity.org/2021/formulas/mathematics/high-school/65x3tt66i7csg0zmcl2f7t2zc9fi70virt.png)
As the length of the toothpick is 3 inches, so d= 3
![\Rightarrow 3=\sqrt {2+h^2}](https://img.qammunity.org/2021/formulas/mathematics/high-school/14qn2i6pj95i8u6o7gtvhna9szg5nnyyhr.png)
![\Rightarrow 9=2+h^2](https://img.qammunity.org/2021/formulas/mathematics/high-school/5rpcajq0ot340t80r7gst7w8jozowi8jx4.png)
![\Rightarrow h^2=9-2=7](https://img.qammunity.org/2021/formulas/mathematics/high-school/clq56s2s1e67hj1dexvh62axcyvfivlfbu.png)
inches.
Hence, the shortest possible length of the box is 2.65 inches.