All of the units sold were priced at $87.00 per unit. Sheffield Back Falls Ltd. uses the perpetual inventory system. Calculate Sheffield Back's cost of goods sold, gross margin, and ending inventory for the month of February using weighted-average. (Round calculations for cost per unit to 2 decimal places, e.g. 10.52 and final answers to 0 decimal places, e.g. 61,052.) Cost of goods sold $ Gross margin $ Ending inventory $