Acircular piece of fabric has a radius of 1.2ft. the fabric sells for $5.40 per ft2. what is the total cost of the circular piece of fabric

Thompson and thompson is a steel bolts manufacturing company. their current steel bolts have a mean diameter of 127 millimeters, and a variance of 36. if a random sample of 35 steel bolts is selected, what is the probability that the sample mean would differ from the population mean by greater than 0.5 millimeters? round your answer to four decimal places.