import math


def haversine_fast(coord1, coord2):
    """Distance in KM between two coordinates, approximated"""
    lat1, lon1 = coord1
    lat2, lon2 = coord2
    x = lat2 - lat1
    y = (lon2 - lon1) * math.cos((lat2 + lat1) * 0.00872664626)
    return 111.319 * math.sqrt(x * x + y * y)