The perimeter of a rectangular field is 342 yards. if the width of the field is 72 yards, what is its length

Answer question above and explain each step : )

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.1. (round your answers to four decimal places.) (a) if the distribution is normal, what is the probability that the sample mean hardness for a random sample of 8 pins is at least 51?

Ill mark the brainliest if you me with the these three questions 7,8,9