Service Revenue Variable Costs Fixed Costs 140 per service call 14 per service call 21,480 per month Homer's Helpers provides locksmith services. One type of service call is to evaluate private residences for security concerns and make recommendations for a safety plan. Use the data below to determine the company's total contribution margin, contribution margin per service call, and contribution margin ratio when 180 service calls are made in the month of June. EE (Click the icon to view the data.) Select the formula labels needed to compute the contribution margin. Then, complete the table to calculate the contribution margin per service call, then the company's total contribution margin. Per call 80 calls Contribution Margin Select the formula to calculate the contribution margin ratio. Contribution Margin Ratio The contribution marain ratio is