Hi Scott,

Since you want the volume in cubic yards I would first convert the 6 feet to yards. There are 3 feet in a yard so 6 feet is 2 yards. I don't remember how many square yards there are in an acre but I can look it up. I would use Google. I typed How many square yards are there in 6 acres? into the google search window and got the response that there are 29040 square yards in 6 acres. Since the dirt is 2 yards deep you need $2 \times 29040$ cubic yards of dirt.

Penny