THE WORLD'S 10 LARGEST FIRMS—WHAT ARE THEIR SOURCES OF ECONOMIES OF SCALE? Find the Forbes 2000 list of the world's largest firms at www.forbes.com/lists. From the top 10 list, select three firms from three different industries and discuss the likely sources of the economies of scale that underlie their large size.

CORPORATE ANNUAL REPORTS—IDENTIFY FIXED AND VARIABLE COSTS Use the Google search engine at www.google.com to locate the home page of a company of your choice. Find and review the company's income statement in its annual report and classify the nonrevenue items as either fixed or variable costs. Are all costs clearly identifiable as either fixed or variable? What item would be considered accounting profit? Would economic profit be higher or lower than this accounting profit