Engberg company installs lawn sod in home yards. the company’s most recent monthly contribution format income statement follows: amount percent of sales sales $ 148,000 100 % variable expenses 59,200 40 % contribution margin 88,800 60 % fixed expenses 20,000 net operating income $ 68,800 required: 1. what is the company’s degree of operating leverage? 2. using the degree of operating leverage, estimate the impact on net operating income of a 15% increase in sales. 3. construct a new contribution format income statement for the company assuming a 15% increase in sales.