In an $L-R-C$ series circuit, the phase angle is 40.0$^\circ$, with the source voltage leading the current. The reactance of the capacitor is 400 $\Omega$, and the resistance of the resistor is 200 $\Omega$. The average power delivered by the source is 150 W. Find (a) the reactance of the inductor, (b) the rms current, (c) the rms voltage of the source.