I figured out the math. Use your Population Density lets say 5000. Now for the average frequency of sex/year divide that number by 365 (days in a year). Then divide the number of minutes for sex by 60 minutes. Then divide by 2 and Square Root it. And Finally Multiply by 100 and you get your answer.
So (Pie)(5000)(65/365)(30/60) = 2/1398.654 = .0014299 AND finally take the square root = .0374 and multiply by 100 = 3.74meters

Took me awhile but I figured something that works out.