>>> from zona_de_cerca import calcula_area_cerca

>>> a = calcula_area_cerca(0, 0, 1, 0)
>>> round(a, 4)
3.1416
>>> a = calcula_area_cerca(-1, 34.6, 0, 0)
>>> round(a, 4)
3764.1307
>>> a = calcula_area_cerca(20, 20, 1, 1)
>>> round(a, 4)
2268.2299
>>> a = calcula_area_cerca(3, 3, 1, 1)
>>> round(a, 4)
25.1327