A 23-kVA, 2300/230-V, 60-Hz, step-down transformer has the following resistance and leakage-reactance values: R1 = 4 ohm, R2 = 0.04 ohm, Xl = 12 ohm, and X2 = 0.12 ohm. The transformer is operating at 75% of its rated load. If the power factor of the load is 0.866 leading, determine the efficiency of the transformer. The load voltage is a reference phasor and with the power factor of 0.866 the load current phasor is I2 = 75<30