3. Cobalt (Co) is the primary component of Co-based alloys used for biomedical implants. Cobalt has an HCP crystal structure, an atomic radius (R) of 0.1253 nm, and a c/a ratio of 1.623 (a and c represent the short and long edge lengths of the HCP unit cell, respectively). Compute the volume of the unit cell for cobalt. The relationship between the atomic radius and the HCP lattice constant is R = a/2. Furthermore, the hexagonal area and lattice constant are related as follows: AHexagon 3-3