\( = {{\log 4} \over {\log 3}}.{{\log 5} \over {\log 4}}.{{\log 6} \over {\log 5}}.{{\log 7} \over {\log 6}}.{{\log 8} \over {\log 7}}.{{\log 9} \over {\log 8}} = {{\log 9} \over {\log 3}}\)
\( = {\log _3}9 = {\log _3}{3^2} = 2\).