1). Power = (voltage)² / (Resistance)
4,500 = (220)² / Resistance
Multiply each side by (resistance) : 4,500 x resistance = (220)²
Divide each side by 4,500 : Resistance = (220)² / 4,500 = 10.76 ohms
2). Power = (voltage) x (Current)
Divide each side by (voltage): Power / voltage = Current
4,500 / 220 = 20.45 Amperes
3). 4,500 watts = 4.5 kilowatts
(4.5 kilowatts) x (4 hours) = 18 kilowatt-hours