1. Calculate APF for FCC unit cell. 3.3 (a) Show for the body-centered cubic crystal structure that the unit cell edge length a and the atomic radius R are related through a=4R/3. (b) Find APF for BCC structure. 3.8 Strontium (Sr) has an FCC crystal structure, an atomic radius of 0.215nm and an atomic weight of 87.62g/mol. Calculate the theoretical density for Sr. 3.10 Calculate the radius of a tantalum (Ta) atom, given that Ta has a BCC crystal structure, a density of 16.6g/cm3, and an atomic weight of 180.9g/mol. 3.34 Within a cubic unit cell, sketch the following directions (Note: only work on a and d): (a) [101] (d) [33] 3.35 Determine the indices for the directions shown in the following cubic unit cell (only for A and B)