Round the cost per unit to 3 decimal places and round your final answers to the nearest dollar. Inventory Costing Methods. Perpetwal Method Using, Uhe data below. assume that Portec Corporation uses the perpetual invertory system. Calculate the value of ending inventory and cost of goods seld at dolar. \begin{tabular}{|l|l|r|r|} \hline & & & Unit \\ \hline & & Units & Cost \\ \hline Beginning Inventory, January 1 & 1,200 & $38 \\ \hline Purchases: & February 11 & 1,500 & $39 \\ \hline & May 18 & 1,400 & 40 \\ \hline & October 23 & 1,100 & 42 \\ \hline Sales: & March 1 & 1,400 & \\ \hline & July 1 & 1,400 & \\ \hline & October 29 & 1,000 & \\ \hline \end{tabular}