#include <stdio.h>#include <stdlib.h>#include <math.h>typedef struct point{double x,y;}point;point P[ 25 ];double r[ 25 ];double cxcarea( point a, point b, double r1, double r2 ){double dc = sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));double r = r1<r2?r1:r2;double R = r1>r2?r1:r2;if ( dc-1e-8 > r+R ) return 0.0;if ( dc+1e-8 < R-r ) return acos(-1.0)*r*r;double a1 = acos((r*r+dc*dc-R*R)/(2.0*r*dc));double a2 = acos((R*R+dc*dc-r*r)/(2.0*R*dc));return a1*r*r+a2*R*R-dc*r*sin(a1);}int cover( int n, double R ){for ( int i = 1 ; i <= n ; ++ i ) {int flag = 1;for ( int j = 1 ; j <= n ; ++ j ) {double s1 = cxcarea( P[i], P[j], R, r[j] );double s2 = acos(-1.0)*r[j]*r[j];if ( s1*2.0 < s2 ) {flag = 0;break;}}if ( flag ) return 1;}return 0;}double b_search( int n ){double l = 0.0,r = 50000.0,m;while ( r-l > 1e-8 ) {m = (l+r)/2.0;if ( cover( n, m ) )r = m;else l = m;}return r;}int main(){int T,N;while ( scanf("%d",&T) != EOF ) while ( T -- ) {scanf("%d",&N);for ( int i = 1 ; i <= N ; ++ i )scanf("%lf%lf%lf",&P[i].x,&P[i].y,&r[i]);printf("%.4lfn",b_search(N));}}
