A. Formula: 2r Radius x 2 is the diameter Answer: so multiply 5x2 and get 10 inches diameter B. Formula: C=2πr Circumference is 2 x pi x radius Answer: multiply 2 x π x 5 to get a circumference of 31.41593 which you should probably write simplified as 31.42 Side Note: Hoping I can get that brainliest lol