You are landscaping your backyard and want to fertilize the lawn. home depot sells supergreen lawn fertilizer in 15-lb bags and each bag cost $16.11 (tax included). each 15 -lb bag is estimated to cover about 3,500 square feet. your lawn is 1/3 of an acre. how much will it cost to fertilize your lawn? assume you cannot purchase partial bags. you have to purchase whole bags. ( hint: 1 acre is 43,560 square feet)