Marginal fact is the amount that total cost (TO) does when the firm increases production by 1 unit of our put (C). Therefore, you ran compu the marginal cost of tine first unit of mutput in the following way Marginal Chat If instead you use variable coat to determine marginal cost, you can compute the marginal cost of the first unit of output in this way: Marginal Cast SIT Similar calculations can be made to complete the remainder of the table. So: Saction: Average and Marginal Cost