Answer to Question #294020 in Physics for nada

Question

In the figure, a cube of edge length a = 3.70 m sits with one corner at the origin of an xyz coordinate system. A body diagonal is a line that extends from one corner to another through the center. Find the angle between each pair of body diagonals.

Answer 1

$$\theta=2\arctan\dfrac{(a/2)}{(a\sqrt2/2)}=70.5°.$$