45% of 20 is what i need and i need u to explain it u

Given a circle with a radius of 4, which is the circumference

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

Which function has the domain x> -11?