python已知三点计算三角形面积详解编程语言

 import math 
 def cal_area(p1,p2,p3): 
 a = float(math.sqrt((p2[0]-p3[0])*(p2[0]-p3[0])+(p2[1]-p3[1])*(p2[1]-p3[1]))) 
 b = float(math.sqrt((p1[0]-p3[0])*(p1[0]-p3[0])+(p1[1]-p3[1])*(p1[1]-p3[1]))) 
 c = float(math.sqrt((p1[0]-p2[0])*(p1[0]-p2[0])+(p1[1]-p2[1])*(p1[1]-p2[1]))) 
 s = (a+b+c)/2 
 S = (s*(s-a)*(s-b)*(s-c))**0.5 
 return S

 def calc_area(p1, p2, p3): 
         (x1, y1), (x2, y2), (x3, y3) = p1,p2,p3 
         return 0.5 * abs(x2 * y3 + x1 * y2 + x3 * y1 - x3 * y2 - x2 * y1 - x1 * y3)