Ответ:НЕ ЗНАЮ

Объяснение:

ПОКА

Python 3.7.2

import math

class Vector(object):

   def __init__(self, starts:dict, ends:dict):

       self.startpoint = starts

       self.endpoint = ends

   def length(self):

       coords = self.coords

       return math.sqrt(sum([coord**2 for coord in coords.values()]))

   @property

   def coords(self):

       xcoord = self.endpoint['x'] - self.startpoint['x']

       ycoord = self.endpoint['y'] - self.startpoint['y']

       try:

           zcoord = self.endpoint['z']- self.startpoint['z']

       except:

           return {'x': xcoord, 'y' : ycoord}

       else:

           return {'x' : xcoord, 'y' : ycoord, 'z' : zcoord}

def GeronTriangleArea(lena, lenb, lenc):

   halfperimeter = (lena + lenb + lenc)/2

   return math.sqrt((halfperimeter * (halfperimeter - lena) * (halfperimeter - lenb) *(halfperimeter-lenc)))

def main():

   firstpoint = (int(input('Первая точка. Х - координата: ')), int(input('First point: Y - coordinates: ')))

   secondpoint = (int(input('Second point. X - coordinates: ')), int(input('Second point. Y - coordinates: ')))

   thirdpoint = (int(input('Third point: X - coordinates: ')), int(input('Third point. Y - coordinates: ')))

   AB = Vector({'x' : firstpoint[0], 'y': firstpoint[1]}, {'x': secondpoint[0], 'y': secondpoint[1]})

   BC = Vector({'x' : secondpoint[0], 'y': secondpoint[1]}, {'x' : thirdpoint[0], 'y': thirdpoint[1]})

   AC = Vector({'x' : thirdpoint[0], 'y': thirdpoint[1]}, {'x' : firstpoint[0], 'y': firstpoint[1]})

   print(f'Triangle area: {GeronTriangleArea(AB.length(), BC.length(), AC.length())}')

if __name__ == '__main__':

   main()

Учись, студент, как усложнять элементарное :D