High-Low Method The manufacturing costs of Rosenthal Industries for the first three months of the year follow: Total Costs Units Produced January $1,890,000 22,500 units February 2,800,000 35,000 March 4,230,000 55,000 Using the high-low method, determine (a) the variable cost per unit and (b) the total fixed cost. a. Variable cost per unit b. Total fixed cost $