Power Factor

A wattmeter, a voltmeter, and an ammeter are installed in an ac circuit, and read 1,000 W, 115 V, and 20 A respectively. What is the circuit's power factor?

Hint
Real Power, $$P$$ , is defined by:
$$$P=V_{rms}\cdot I_{rms}\cdot cos\:\theta$$$
$$$P=V\cdot I\cdot cos\:\theta$$$
Solving for $$cos\:\theta$$ :
$$$cos\:\theta=\frac{P}{V\cdot I} $$$
Since $$cos\:\theta=pf$$
$$$pf=cos\:\theta=\frac{P}{V\cdot I}=\frac{1,000}{115\cdot 20}=0.43$$$
0.43