Answer: the length of the needle is 8.49 inches.
Step-by-step explanation:
The diagram of the clear cube is shown in the attached photo. From the diagram, a right angle triangle ABC is formed.
BC represents the diagonal of a face of the cube.
AB represents the the side length of the clear cube.
AB = h represents the length of the needle
To determine AB, we would apply Pythagoras theorem which is expressed as
Hypotenuse² = opposite side² + adjacent side²
Therefore
AB² = 6² + 6² = 72
AB = √72
AB = 8.49