If this is log to the base 10, then log y = 3.8 means that y = 10^3.8
$${\mathtt{y}} = {{\mathtt{10}}}^{{\mathtt{3.8}}} \Rightarrow {\mathtt{y}} = {\mathtt{6\,309.573\: \!444\: \!801\: \!932\: \!494\: \!3}}$$
If it is log to a different base, say, b, then y = b^3.8.