Answer:
35.26°
Explanation:
You have to visualize this or draw a diagram
If a cube has side a, the face diagonal of the cube is √2a . The diagonal of the cube is √3a
One side of length a, another side of length √2a (face diagonal) and the third of √3a form a right triangle with the angle opposite √3a being the 90° angle
Therefore we can find the angle
which the cube diagonal makes with the face diagonal using the fact

