Calculate phase angle of LC||R circuit
Xc=1/2pifC  (you used L instead of C in your equation).  Also, if you use a minus sign for Xc, then you must add Xl an Xc, not subtract them.  You equations are correct if you remove the minus sign from Xc.
The phase angle of the input impedance is:  Θ = arctan(R/(Xl-Xc). Substituting your numbers, Xl=150.80, Xc=154.22, Θ=-88.89°.