Let side of the cube =a Then OG,BE and AD,CF will be four diagonals. d.r.'s of OG=a,a,a=1,1,1 d.r.'s of BE=−a,−a,a=1,1,−1 d.r.'s of AD=−a,a,a=−1,1,1 d.r.'s of CF=a,−a,a=1,−1,1 Let d.r's of line be l,m,n. Therefore angle between line and diagonal\
