How many diagonals are there in a regular polygon

Ben is three times as old as samantha, who is two years older than half of michel's age. if michel is 12. how old is ben?

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?

Secant be and cf intersect at point d inside a what is the measure of cde