Using your algebra skills stepwise:
(x/100)*(1/3) = (5/9)
(x/100) = (5/9)*(3/1)
(x/100) = 15/9
x = (15/9)*100
x = 1500/9 = 500/3 = 16.6666
x = 16.67 % as a percent to two decimal places
* Note: The use of 100 in the algebra was not entirely necessary, but using 100 often helps students with problems using percent notation.