power factor

I know you can find reactive power out from the alternative formula below, but using the formula "P(W) = V(V) × I(A) × cos φ", how do you obtain the complex power phase angle (φ) from knowing the Voltage, Power and Current? Alternative formula: Reactive Power=√ (Apparent Power²– True power²)...

So a couple of months back I got a pair of Alto True Sonic TS210 PA speakers for outdoor events. However the wattage rating of them is strange to say the least. According to https://www.altoproaudio.com/downloads/Alto-Professional-TS210-Spec-Sheet.pdf, they have a continuous RMS power rating...