To find the atomic radius of an element with a body-centered cubic (bcc) structure, we need to understand the geometry of the bcc unit cell.$\\$In a bcc structure, the atoms are located at the corners of the cube and one atom is at the center. The relation between the atomic radius $r$ and the edge length $a$ of the cube is given by:$\\$• The body diagonal of the cube contains $2$ atomic radii plus the diameter of the central atom.$\\$