to figure out how long is 1 round of the circle we will find circumfrence of circle. C = 2 * π * R. So the r = 1/2 of the diameter which is going to be 1.5 miles. so we multiply 2 by π by 1.5 which gives us an answer of 9.4 something Then times it by four to get ur final answer which is going to be 38 miles after rounding.
