For each variable cost per unit listed below, determine the total variable cost when units produced and sold are 45, 90, and 180 units. Direct materials $ 20 Direct labor 66 Variable overhead 10 Sales commission 12 Begin by calculating total variable cost for each variable cost per unit listed, and the total variable cost when sales are 45 units. Then calculate the total variable cost when sales are 90 and 180 units, respectively