Maria's Magic Mirror Shop had the following activity for December: Total mirrors sold: 20,000 Total sales revenue: 700,000 Total fixed costs: 250,000 Total variable costs: 420,000 What was Maria's Margin of Safety, measured in sales dollars? The contribution margin ratio is 40% for the Northern Company. The break-even amount of revenue is $420,000. If Northern's target pre-tax profit is $70,000, revenue would have to be