Duncan had revenues of $770,000 in March. Fixed costs in March were $207,900 and profit was $215,600. a. What was the contribution margin percentage? Contribution Margin % b. What monthly sales volume (in dollars) would be needed to break-even? (Do not round intermediate calculations. Round final answers to the nearest whole dollars.) Total Sales Volume Needed c. What was the margin of safety for March? (Do not round intermediate calculations. Round final answers to the nearest whole dollars.) Margin of Safety