#include <bits/stdc++.h>

#define readFile freopen("in.txt","r",stdin)
#define writeFile freopen("out.txt","w",stdout)
#define fastio ios_base::sync_with_stdio(false)

using namespace std;

const int N = 100010;
const long long M = 1e9 + 7;

#define eps 1e-9
#define PI acos(-1.0)

double sqr(double x){
    return x*x;
}

struct point{
    double x,y;
    point():x(0),y(0){}
    point(double x, double y):x(x),y(y){}

    double dist(const point &p){
        return hypot(this->x-p.x,this->y-p.y);
    }
};

struct circle{
    point p;
    double r;
    circle():p(),r(0){}
    circle(point p, double r):p(p.x,p.y),r(r){}
};

struct line{
    // ax + by + c = 0;
    double a,b,c;
    line(){}
    line(double a, double b, double c):a(a),b(b),c(c){}
    line(point p1, point p2){
        if(abs(p1.x-p2.x) < eps){ // vertical
            a = 1.0;
            b = 0.0;
            c = -p1.x;
        }
        else{
            a = -(p1.y-p2.y)/(p1.x-p2.x);
            b = 1.0;
            c = -(a*p1.x)-p1.y;
        }
    }
};

struct triangle{
    double a,b,c;
    triangle(){}
    triangle(point p1, point p2, point p3){
        a = p1.dist(p2);
        b = p2.dist(p3);
        c = p1.dist(p3);
    }

    double area(){
        double sp = (a+b+c)/2.0;
        double res = sp*(sp-a)*(sp-b)*(sp-c);
        return sqrt(res);
    }

    double findTheta(){
        double aa = a, bb = b, cc = c;
        if(bb > aa) swap(aa,bb);
        if(cc > aa) swap(aa,cc);
        double costheta = (sqr(bb)+sqr(cc)-sqr(aa))/(2.0*bb*cc);
        return acos(costheta);
    }
};

int lineCircleIntersection(circle cr, line l, point &p1, point &p2){
    if(abs(l.b)<eps){ // Vertical line, the equation is already solved for x .
        double a = 1.0;
        double b = -2.0 * cr.p.y;
        double c =  sqr(l.c/l.a-cr.p.x) + sqr(cr.p.y) - sqr(cr.r);
        double d = sqr(b) - 4.0 * a * c;
        if(d+eps < 0) return 0; // No intersection .
        if(abs(d) < eps){
            p1.x = l.c/l.a;
            p1.y = -b/(2.0*a);
            return 1; // Tangent line .
        }
        double dd = sqrt(d);
        p1.x = p2.x = l.c/l.a;
        p1.y = (-b+dd)/(2.0*a);
        p2.y = (-b-dd)/(2.0*a);
        return 2; // Intersect in two points .
    }
    else{
        double a = 1.0 + l.a;
        double b = 2.0 * (l.a*l.c - cr.p.x + cr.p.y*l.a);
        double c = sqr(cr.p.x) + sqr(cr.p.y) + sqr(l.c) - sqr(cr.r) - (2.0*cr.p.y*l.c);
        double d = sqr(b) - 4.0 * a * c;
        if(d+eps < 0) return 0; // No intersection .
        if(abs(d) < eps){
            p1.x = -b/(2.0*a);
            p1.y = -p1.x - l.c;
            return 1; // Tangent line .
        }
        double dd = sqrt(d);
        p1.x = (-b+dd)/(2.0*a);
        p1.y = -(p1.x*l.a) - l.c;
        p2.x = (-b-dd)/(2.0*a);
        p2.y = -(p2.x*l.a) - l.c;
        return 2; // Intersect in two points .
    }
}

int main() {
#ifndef ONLINE_JUDGE
    readFile;
#endif
    fastio;
    int t,tt = 1; cin >> t;
    while(t--){
        double x,y,z; cin >> x >> y >> z;
        circle c(point(x,y),z);
        double x1,y1,x2,y2; cin >> x1 >> y1 >> x2 >> y2;
        point p1(x1,y1),p3(x2,y2);
        point p2(p1.x,p3.y);
        line l1(p2,p3), l2(p1,p2);

        point pt1,pt2,cl1,cl2;
        int res = lineCircleIntersection(c,l1,pt1,pt2);
        if(res==2){
            if(pt1.x > pt2.x) cl1 = pt1;
            else if(pt2.x > pt1.x) cl1 = pt2;
            else if(pt1.y < pt2.y) cl1 = pt1;
            else cl1 = pt2;
        }
        else cl1 = pt1;

        res = lineCircleIntersection(c,l2,pt1,pt2);
        if(res==2){
            if(pt1.y < pt2.y) cl2 = pt1;
            else if(pt2.y < pt1.y) cl2 = pt2;
            else if(pt1.x > pt2.x) cl2 = pt1;
            else cl2 = pt2;
        }
        else cl2 = pt1;

        triangle t1(cl1,cl2,c.p);
        double cseg = ((t1.findTheta()*sqr(c.r))/2.0)-t1.area();

        triangle t2(cl1,p2,cl2);
        double ans = cseg + t2.area();

        cout << "Case " << tt++ << ": ";
        cout << fixed << setprecision(8) << ans << "\n";
    }
    return 0;
}