//Nightmare05

include<bits/stdc++.h>

using namespace std;

define sp << " " <<

define mod 1000000007

define mp make_pair

define pb push_back

define int long long

define double long double

define INF (1e18+13)

define PI 3.1415926535898

int power(int p,int j) { int res=1; p=p%mod; while(j>0) { if(j&1) res=(res*p)%mod; j=j>>1; p=(p*p)%mod; } return res; }

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int dice(int d,int p) { uniform_int_distribution uid(d,p);//specify l and s. return uid(rng) ; } /* int read() { int cc = getc(stdin); for (;cc < '0' || cc > '9';) cc = getc(stdin); int ans = 0; for (;cc >= '0' && cc <= '9';) { ans = ans * 10 + cc — '0'; cc = getc(stdin); } return ans; }

inline void print(int n) { if (n == 0) { putchar('0'); putchar('\n'); } else if (n == -1) { putchar('-'); putchar('1'); putchar('\n'); } else { char buf[20]; buf[19] = '\n'; int i = 18; while (n) { buf[i--] = n % 10 + '0'; n /= 10; } while (buf[i] != '\n') putchar(buf[++i]); } }

int n;

vector<vector> mat_mul(vector<vector> a,vector<vector> b) { int n=5; vector<vector> ans2(n,vector(n,0)); for(int i=0;i<n;i++) { for(int j=0;j<n;j++) { for(int ans2=0;ans2<n;ans2++) { ans2[i][j]+=((a[i][ans2]*b[ans2][j])%mod); ans2[i][j]%=mod; } } } return ans2; }

vector<vector> pow_mat(vector<vector> mat_a,int p) { if(p==1) return mat_a; vector<vector> temp=pow_mat(mat_a,p/2); vector<vector> res=mat_mul(temp,temp); if(p&1) res=mat_mul(res,mat_a); return res; } */

double s(double m1,double m2,double c1,double c2,double c3,double c4) { double x1,x2,x3,x4,y1,y2,y3,y4; x1=(c2-c1)/(m1-m2); x2=(c3-c2)/(m2-m1); x3=(c4-c3)/(m1-m2); x4=(c1-c4)/(m2-m1); y1=m1*x1+c1; y2=m2*x2+c2; y3=m1*x3+c3; y4=m2*x4+c4; double d[4]; d[0]=(y2-y1)*(y2-y1)+(x2-x1)*(x2-x1); d[1]=(y3-y2)*(y3-y2)+(x3-x2)*(x3-x2); d[2]=(y4-y3)*(y4-y3)+(x4-x3)*(x4-x3); d[3]=(y1-y4)*(y1-y4)+(x1-x4)*(x1-x4); sort(d,d+4); if(abs(d[3]-d[0])<0.01) return sqrt((d[0]+d[3])/2)+26.0; else return -1; }

int32_t main() { ios::sync_with_stdio(false); cin.tie(0); cout.tie(0); //freopen("elimination_validation_input.txt", "r", stdin); //freopen("output.txt", "w", stdout); int t; cin >> t; while(t--) { double dp=-1; double x1,x2,x3,x4,y1,y2,y3,y4; pair<double,double> a[4]; cin >> a[0].first >> a[0].second >> a[1].first >> a[1].second >> a[2].first >> a[2].second >> a[3].first >> a[3].second; for(int j=0;j<6;j++) { if(j==1||j==3||j==5) swap(a[2],a[3]); if(j==2||j==4) swap(a[1],a[3]); x1=a[0].first; y1=a[0].second; x2=a[1].first; y2=a[1].second; x3=a[2].first; y3=a[2].second; x4=a[3].first; y4=a[3].second; for(double i=0.0;i<=1.0;i+=0.0001) { double m1=i*PI; m1=tan(m1); double c1=y1-m1*x1,c3=y3-m1*x3; double m2=-1/m1; if(m1==0.00000) m2=tan(PI/2); double c2=y2-m2*x2,c4=y4-m2*x4; int h=1; double p[3]; p[0]=y2-m1*x2-c1; p[1]=y3-m1*x3-c1; p[2]=y4-m1*x4-c1; if(abs(p[0])>abs(p[1])||abs(p[2])>abs(p[1])) h=0; sort(p,p+3); for(int z=0;z<3;z++) if(abs(p[z])<0.0000000001) h=0; if(p[0]*p[2]<0) h=0; p[0]=y1-m2*x1-c2; p[1]=y3-m2*x3-c2; p[2]=y4-m2*x4-c2; if(abs(p[0])>abs(p[2])||abs(p[1])>abs(p[2])) h=0; sort(p,p+3); for(int z=0;z<3;z++) if(abs(p[z])<0.0000000001) h=0; if(p[0]*p[2]<0) h=0; p[0]=y2-m1*x2-c3; p[1]=y1-m1*x1-c3; p[2]=y4-m1*x4-c3; if(abs(p[0])>abs(p[1])||abs(p[2])>abs(p[1])) h=0; sort(p,p+3); for(int z=0;z<3;z++) if(abs(p[z])<0.0000000001) h=0; if(p[0]*p[2]<0) h=0; p[0]=y2-m2*x2-c4; p[1]=y3-m2*x3-c4; p[2]=y1-m2*x1-c4; if(abs(p[1])>abs(p[0])||abs(p[2])>abs(p[0])) h=0; sort(p,p+3); for(int z=0;z<3;z++) if(abs(p[z])<0.0000000001) h=0; if(p[0]*p[2]<0) h=0; if(h) dp=max(dp,s(m1,m2,c1,c2,c3,c4)); } } if(dp<26) cout << -1 << endl; else cout << fixed << setprecision(2) << dp << endl; } return 0; }