Step 1 :

(a)

The function is

Marginal cost function is the derivative of cost function.

Differentiate with respect to x.

The marginal cost function is .

Step 2 :

(b)

Substitute in .

The marginal cost at the production level of 200 is $ 32/yard.

means the cost of producing 201^st  yard.

Step 3 :

(c)

The actual cost of producing the item.

Solution :

(a)

(b) $ 32/yard ; means the cost of producing 201^st  yard

(c) $ 32.20.