The steps you have are correct. I'll fill in the gap between step 2 and step 3.
[tex]0.4245 = \frac{2.5}{\text{x}}\\\\0.4245\text{x} = 2.5\\\\\text{x} = \frac{2.5}{0.4245}\\\\\text{x} = 5.8892815\\\\\text{x} = 5.9\\\\[/tex]
I multiplied both sides by x, then divided both sides by 0.4245 to isolate the variable.
With the exception of 2.5, every other decimal value mentioned is approximate.
