Question is in the picture, tysm for the help! (showing steps would be greatly appreciated too)

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?

This figure consists of a rectangle and semicircle. what is the perimeter of this figure use 3.14 for pi 60.84m 72.84m 79.68m 98.52m

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?