By using triangle law, Similarly, AC=AO+OB AD=AO+OC AE=AO+OE AF=AO+OF AG=AO+OG AH=AO+OH Now, adding all vectors AB+AC+AD+AE+AF+AG+AH =7AO+(OB+OC+OD+OE+OF+OG+OH) . . . (i) By using cyclic vector, OA+OB+OC+OD+OE+OF+OG+OH=0 ⇒OB+OC+OD+OE+OF+OG+OH =0−OA=0+AO Substituting in Eq. (i), we get AB+AC+AD+AE+AF+AG+AH=7AO+AO=8AO =8(2
