// Exa 1.22.1
clc;
clear;
close;
// Given data
a = 4.8;// in Å
h = 2;
k = 1;
l = 1;
d = a/(sqrt( ((h)^2) + ((k)^2) + ((l)^2) ));// in Å
disp(d,"The distance between d_211 plains in Å is");