using proportion in similar triangle, then
let x be the length of the tower's shadow
[tex]\frac{9}{16.2}[/tex] = [tex]\frac{7}{x}[/tex] ( cross- multiply )
9x = 113.4 ( divide both sides by 9 )
x = [tex]\frac{113.4}{9}[/tex] = 12.60 m ( to the nearest hundredth )