Atomic Concentration of a Miller index on FCC

u_know_who

1. The problem statement, all variables and given/known data
Find the atomic concentration of Miller index [itex](0\overline{1}2)[/itex] in a FCC crystal.


2. Relevant equations
Radius of the circle at a height "h" from the center of a sphere (of radius R) is √(R^2-h^2).


3. The attempt at a solution

Sorry can't yet solve.