#include <cmath>
#include <cstdio>
using namespace std;

const long double PI=3.14159265358979323846;
int T;
int l1, l2, a, b;
long double a_, b_;
long double sqr(long double x){ return x*x; }
long double S(long double alpha, long double r){
    return alpha*r*r;
}
long double tran(long double alpha){ return PI*alpha/180; }
long double S1, S2, S3, S4;
long double l3, l4, c;

int main(){
    scanf("%d", &T);
    while (T--){
        scanf("%d%d%d%d", &l1, &l2, &a, &b);
        a_=tran(a); b_=tran(b);
        S1=S(a_, l1+l2);
        S2=S(b_, l2);
        if (b<=90){
            printf("%.15Lf\n", S1+S2);
            continue;
        }
        long double b1=PI-b_;
        l3=sqrtl(sqr(l1)+sqr(l2)-2*l1*l2*cosl(b1));
        if (sqr(l3)+sqr(l2)-sqr(l1)>=0){  //用高代替l3
            l3=l1*sinl(b1);
            c=b_-PI/2;
        } else c=asinl(l2/l3*sinl(b1));
        S3=l1*l3*sinl(c)-S(c, l3);
        if (c>2*a_){  //要减一块
            l4=l3*sinl(b1+c)/sinl(2*a_+b1);
            S4=l3*l4*sin(c-2*a_)-S(c-2*a_,l3);
        } else S4=0;
        printf("%.15Lf\n", S1+S2+S3-S4);
    }
    return 0;
}