Last One!

A farmer has a triangular field with sides of 240 ft., 300 ft., and 360 ft. He wants to apply fertilizer to the field. If one 40-pound bag of fertilizer covers 6000 square feet, how many bags must he buy to cover the field.

I drew a diagram and have a feeling I need to use these equations

Law of Cosines

Area of a triangle (1/2 ab sinC)

I just don't know how I would go about it