1 #include <iostream>
2 #include <cstdio>
3 #include <cstring>
4 #include <algorithm>
5 #include <cmath>
6
7 using namespace std;
8
9 struct circle
10 {
11 double x,y,r;
12 }c[25];
13
14 double exp1 = 10e-9;
15 double reans[25];
16
17 double iabs(double a)
18 {
19 if(a<0)
20 return -a;
21 else
22 return a;
23 }
24
25 double mianji(circle c1)
26 {
27 return c1.r*c1.r*acos(-1);
28 }
29
30 double jieguo(circle c1,circle c2,double r)
31 {
32 double b = sqrt((c1.x-c2.x)*(c1.x-c2.x)+(c1.y-c2.y)*(c1.y-c2.y));
33 double c = c2.r;
34 double a = r;
35 if(a+c<=b)
36 return 0;
37 if(b<=iabs(a-c))
38 {
39 return min(a,c)*min(a,c)*acos(-1);
40 }
41 double cos1 = (b*b+c*c-a*a)/2/c/b;
42 double s1 = c*c*acos(cos1);
43 double cos2 = (a*a+b*b-c*c)/2/a/b;
44 double s2 = a*a*acos(cos2);
45 double s3 = a*b*sin(acos(cos2));
46 double s4=s1+s2-s3;
47 return s4;
48 }
49
50 int main()
51 {
52 int T;
53 scanf("%d",&T);
54 while(T--)
55 {
56 int n;
57 scanf("%d",&n);
58 for(int i=0;i<n;i++)
59 {
60 scanf("%lf%lf%lf",&c[i].x,&c[i].y,&c[i].r);
61 }
62 memset(reans,0,sizeof(reans));
63 for(int i=0;i<n;i++)
64 {
65 for(int t=0;t<n;t++)
66 {
67 double s=c[t].r*c[t].r*acos(-1)/2;
68 double mar=sqrt((c[i].x-c[t].x)*(c[i].x-c[t].x)+(c[i].y-c[t].y)*(c[i].y-c[t].y))+c[t].r;
69 double mir=sqrt((c[i].x-c[t].x)*(c[i].x-c[t].x)+(c[i].y-c[t].y)*(c[i].y-c[t].y));
70 double ans=0;
71 double r=mir;
72 while(iabs(ans-s)>exp1)
73 {
74 if(ans<s)
75 {
76 mir=r;
77 r=(mir+mar)/2;
78 ans=jieguo(c[i],c[t],r);
79 }
80 else
81 {
82 mar=r;
83 r=(mir+mar)/2;
84 ans=jieguo(c[i],c[t],r);
85 }
86 }
87 if(reans[i]<r)
88 reans[i]=r;
89 }
90 }
91 double ss=reans[0];
92 for(int i=1;i<n;i++)
93 {
94 if(reans[i]<ss)
95 ss=reans[i];
96 }
97 printf("%.4lf\n",ss);
98 }
99 return 0;
100 }
