Answer:
[tex]6.56\times10^{-7}[/tex]
Step-by-step explanation:
[tex]1nm[/tex] is equal to [tex]1\times 10^{-9}m[/tex] so you have the next relation
[tex]\frac{1nm}{1\times 10^{-9}m} = \frac{656nm}{x}[/tex]
Then isolating [tex]x[/tex] you have
[tex]x = \frac{6.56\times 10^{2}nm \cdot 1\times 10^{-9}m}{1nm} = 6.56\times 10^{-7}m[/tex]
