Does anyone know how to do number 3

What is the solution to the equation in the & show work i’m very

What is the area of the shaded sector?

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $36.98. find the probability that a randomly selected bill will have an amount greater than $173, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?