You are given three identical bricks, shaped as rectangular parallelepipeds, and a measuring tape or a ruler .
Your task is to evaluate the length of the inner diagonal of a brick.
Same answer. I'm just enjoying the different wordings.
Lay two bricks one on top of the other, and the third alongside these two. Imagine a fourth brick laid atop the third brick. You can measure this imagined brick's 3d diagonal from the diagonally opposed top corners of the existing top bricks.