Rounding to three significant figures
[tex]\text{ 3.85 x 10}^{-9}[/tex]done
To round to significant figures, just consider the numbers before the decimal point (3) , and consider all the numbers different from zero after the decimal point (85).
The three significant figures are 3, 8 and 5.
The numbers x 10^-9 are not consider as significant figures.
