Answer:
990 feet.
Explanation:
To calculate the feet of metal that the last fabricator will sell, you just have to substract from the total feet needed the amount of metal that have been already ordered to the other fabricators.
Total metal duct work= Fabricator 1+ Fabricator 2+ Fabricator 3+ Fabricator 4
If you clear the equation it would be:
F4= Total- F1- F2- F3
F4= 5840- 2,500- 1,200- 1150
F4= 990 ft.