Two items are omitted from each of the following summaries of balance sheet and income statement data for two corporations for the year 2019, Sheffield Corp. and Riverbed Enterprises. Determine the missing amounts. Sheffield Corp. Riverbed Enterprises Beginning of year: Total assets $128,040 $170,280 Total liabilities 112,200 (c) Total stockholders' equity (a) 99,000 End of year: Total assets Total liabilities Total stockholders' equity Changes during year in stockholders' equity: 211,200 158,400 52,800 237,600 66,000 171,600 Additional investment (b) 33,000 Dividends 31,680 (d) Total revenues 283,800 231,000 132,000 72,600 Total expenses