Well you have to find the radius you have to divide the diameter by 2 which will get you 15. the equation to find circumference is c=2PIEr (sorry didn't have the pie symbol). Anyways just plug in the numbers and you get you answer. Hope this help.
3, 20 bills 60 dollars add 1, 10 bill to get to 70 dollars add 1, 5 bill you get 75 dollars add 2,1 bills to get 77 dollars finaly 1 quarter to get 77 dollars and 25 cents
