How many tetrahedral voids are occupied in diamond? (in percentage)

Show that in a cubic close packed $(ccp)$ structure,eight tetrahedral voids are present per unit cell.

In a crystalline solid with the formula $AB_2O_4$,the oxide ions are arranged in a cubic close-packed $(CCP)$ lattice,while the cations $A$ are present in tetrahedral voids and cations $B$ are present in octahedral voids. What are the percentages of tetrahedral and octahedral voids occupied by $A$ and $B$ respectively?

What is the full form of $fcc$?

What are the number of octahedral and tetrahedral voids in $0.3 \ mol$ of a substance respectively,if it forms an $hcp$ structure?

$A$ metal forms an $fcc$ structure. Calculate the volume of the $fcc$ unit cell in $\text{cm}^3$ if the void volume is $1.66 \times 10^{-23} \text{ cm}^3$.