Step-by-step explanation:
The conversion for parsecs into meters is
1 parsec (pc) = [tex]3.09×10^{16}\:\text {m}[/tex]
So if Proxima Centauri is [tex]4×10^{13}\:\text{m}[/tex] away, then in terms of parsecs, this distance is
[tex]4×10^{13}\:\text{m}×\left(\dfrac{1\:\text{parsec}}{3.09×10^{16}\:\text{m}}\right)[/tex]
[tex]\;\;\;\;\;= 1.2×10^{-3}\:\text{parsec}[/tex]
