sometimes because if the radios is 2 the the circumference would equal 12.56 because you multiply 2 time 2 to get the diameter then you multiply the answer which is 4 by 3.14 and it equals 12.56. For area you need the radios which is 2, the you multiply it to the second power to get 4 then you multiply 4 by 3.14 to get 12.56
