python初学者，完全不懂，求各位解答

Question

求思二维上三个不同点组成的三角形面积，结果保留四位小数，用编码来解决

Answer 1

先算出两两之间的距离，再用海伦公式算面积

import math
def cal_area(p1,p2,p3):
    '''
    :param 
    p: [x,y]
    :return 
    S: area of triangle
    '''
    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
s = cal_area([2.3,2.5],[6.4,3.1],[5.1,7.2])
print("{}".format(s))

8.795