Bài 1
From math import sqrt
x1=(input())
x2=(input())
y1=(input())
y2=(input())
dAB=sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1))
Print("{:.3}".format(dAB))
Bài 2
From math import sqrt
p=(input())
a=(input())
c=(input())
p=(a+b+c)/2
s=sqrt((a+b+c)/2*(((a+b+c)/2)-a)*(((a+b+c)/2)-b)*(((a+b+c)/2)-c))
Print("{:.3}".format(p))
Print("{:.3}".format(s))