Find out the ratio of maximum number of triangular voids and rectangular voids formed by nine atoms according to HCP and square close packing in 2D respectively

The number of tetrahedral voids are formed if the number of atoms in a crystal is N/2

You are given 6 identical balls. What is the maximum number of square voids and triangular voids ( in separate arrangements) that can be created?

You are given 4 identical balls. What is the maximum number of square voids and triangular voids (in separate arrangements) that can be created ?

You are given 6 identical balls. What is the maximum number of square voids and triangular voids (in separate arrangements) that can be created ?

The difference in coordination numbers of hexagonal close packing in 3D and square close packing in 2-D, of identical spheres is:

Which of the following option(s) is//are incorrect if an arrangement is formed by two different atoms A and B such that B forms cubic close packing and A atoms occupy all the octahedral voids without causing any distortions. [Given : Edge length of cube = a, Radius of atom A= r_(a), Radius of atom B = r_(b)]