High-Low Method The manufacturing costs of Rosenthal Industries for the first three months of the year follow: Total Costs Production January $222,300 1,330 units February 306,770. 2,460 March 345,800 3,230 Using the high-low method, determine (a) the variable cost per unit and (b) the total fixed cost. a. Variable cost per unit $ 65 b. Total fixed cost $ 135,850