LOJ 1331

#include <stdio.h>
#include <math.h>
int main() {
    double r1,r2,r3,x,y,z,X,Xr,Y,Yr,Z,Zr,tarea,s,area;
    int n,i;
    scanf("%d",&n);
    for(i=1;i<=n;i++){
        scanf("%lf%lf%lf",&r1,&r2,&r3);
        x = r2 + r3;
        y = r1 + r3;
        z = r1 + r2;
        s = (x+y+z)/2;
        tarea = sqrt(s*(s-x)*(s-y)*(s-z));
        X = acos((y*y+z*z-x*x)/(2*y*z));
        Y = acos((z*z+x*x-y*y)/(2*x*z));
        Z = acos((x*x+y*y-z*z)/(2*x*y));
        area = tarea - (0.5)*(r1*r1*X+r2*r2*Y+r3*r3*Z);
        printf("Case %d: %.08lf\n",i,area);
    }
    return 0;
}