
    Write a function to calculate the coverage area of a bus stop's spherical sensor detection zone, where the sensor monitors passenger presence in a three-dimensional space around the stop. The detection zone extends equally in all directions from the bus stop's sensor hub, forming a perfect sphere with radius r meters that can detect waiting passengers anywhere on its surface.
    

    
import math

def surfacearea_sphere(r):
    """
    Write a function to calculate the coverage area of a bus stop's spherical sensor detection zone, where the sensor monitors passenger presence in a three-dimensional space around the stop. The detection zone extends equally in all directions from the bus stop's sensor hub, forming a perfect sphere with radius r meters that can detect waiting passengers anywhere on its surface.
    

    """
import math

def surfacearea_sphere(r):
    """
    Write a function to calculate the coverage area of a bus stop's spherical sensor detection zone, where the sensor monitors passenger presence in a three-dimensional space around the stop. The detection zone extends equally in all directions from the bus stop's sensor hub, forming a perfect sphere with radius r meters that can detect waiting passengers anywhere on its surface.
    

    """
    surfacearea = 4 * math.pi * r * r
    return surfacearea