Iron forms a crystal lattice where each central atom appears at the center of a cube, the

Question:

Iron forms a crystal lattice where each central atom appears at the center of a cube, the corners of which correspond to additional iron atoms, as in Figure 23. Use the dot product to find the angle β between the line segments from the central atom to two adjacent outer atoms. Take the central atom to be situated at the origin and the corner atoms to occur at (±1, ±1, ±1).