eriodic inventory using fifo, lifo, and weighted average cost methods the units of an item available for sale during the year were as follows: jan. 1 inventory 12 units at $3,600 $43,200 aug. 7 purchase 18 units at $3,800 68,400 dec. 11 purchase 12 units at $4,000 48,000 42 units $159,600 there are 20 units of the item in the physical inventory at december 31. the periodic inventory system is used. determine the inventory cost using (a) the first-in, first-out (fifo) method; (b) the last-in, first-out (lifo) method; and (c) the weighted average cost method (round per unit cost to two decimal places and your final answer to the nearest whole dollar). a. first-in, first-out (fifo) $fill in the blank 1 b. last-in, first-out (lifo) $fill in the blank 2 c. weighted average cost $fill in the blank 3