A solid has bcc structure.the distance of nearest approach b/w two atom is 1.73 Amstrong. What is the edge length of the cell?

As the solid has bcc structure,

the distance of nearest approach b/w two atoms would be equal to half the diagonal distance 

i.e.              √3⁄2 of the edge length = 1.73

solving which you will get edege length = 2 Å