A Chapter 1: Applying Excel 2. 3 Data Sales $ 4 75,210 5 Variable costs: $ 6 Cost of goods sold Variable selling Variable administrative $ 52,320 5,232 5,014 $ 8 Fixed costs: $ 10 Fixed selling 2,500 1,500 $ Fixed administrative (a) What is the gross margin now? Gross margin (b) What is the net operating income now? Net operating income (c) What is the contribution margin now? Contribution margin