Okay. So 25 cents is expressed as 0.25. it is $0.25 for a square foot of grass seed. To find the cost for 55,000 square feet of grass seed, all you have to do is multiply the cost per square foot by the amount of square feet total. In this case, we would multiply 55,000 by 0.25. 55,000 * 0.25 is 13,750. There. The total cost would be $13,750.