This document is a worksheet in Portuguese for an electrical engineering course module on three-phase alternating current. It contains 4 practice problems. Problem 1 asks about line and phase voltages in a balanced three-phase system. Problem 2 presents the formulas for calculating active and reactive power in wye and delta connections. Problem 3 justifies that power formulas are the same but consumption can differ between wye and delta. Problem 4 calculates current, impedance, powers, and provides a diagram for a resistive load connected wye.