
    Calculate the total boundary distance of a delivery zone that forms a perfect circle around a central distribution hub, where delivery vehicles must serve customers along the perimeter. The radius of this circular service area is measured from the hub to the zone's edge in kilometers, and finding the total perimeter distance is essential for route planning and resource allocation.
    

    
def circle_circumference(r):
    """
    Calculate the total boundary distance of a delivery zone that forms a perfect circle around a central distribution hub, where delivery vehicles must serve customers along the perimeter. The radius of this circular service area is measured from the hub to the zone's edge in kilometers, and finding the total perimeter distance is essential for route planning and resource allocation.
    

    """
def circle_circumference(r):
    """
    Calculate the total boundary distance of a delivery zone that forms a perfect circle around a central distribution hub, where delivery vehicles must serve customers along the perimeter. The radius of this circular service area is measured from the hub to the zone's edge in kilometers, and finding the total perimeter distance is essential for route planning and resource allocation.
    

    """
    perimeter = 2 * 3.1415 * r
    return perimeter