Answer
$P^{}= 209$ kPa
Work Step by Step
The stagnation pressure in this case is identical to the inlet pressure since the inlet velocity is negligible. It remains constant throughout the nozzle since the flow is isentropic, $$
P_0=P_{\mathrm{i}}=1.2 \mathrm{MPa}
$$ From Table $A-32$ at $\mathrm{Ma}_{\mathrm{e}}=1.8$, we read $P_{\mathrm{e}} / P_0=0.1740$.
Thus, $$
P=0.1740 P_0=0.1740(1.2 \mathrm{MPa})=\mathbf{0 . 2 0 9} \mathrm{MPa}=\mathbf{2 0 9} \mathbf{k P a}
$$
