What is the circumference of this circle

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?

An arc subtends a central angle measuring 7pi/4 radians what fraction of the circumference is this arc?

Afarmer has decided to divide his land area in half in order to plant soy and corn. calculate the area of the entire area so he knows how much soil is needed. each bag of soil covers 20 square yards. how many bags should the farmer purchase? (4 points) 1 bag 2 bags 3 bags 4 bags