#include <bits/stdc++.h>
using i64 = int64_t;
using f64 = double;
using f128 = long double;

const f64 pi = acos(-1.0);
constexpr f64 eps = 1e-9;

inline int dcmp(double x) {
	return (x > eps) - (x < -eps);
}

inline f64 Carea(f64 alpha, f64 r) {
	return alpha * r * r;
}

void solve() {
	double l1, l2, alpha, beta;
	scanf("%lf%lf%lf%lf", &l1, &l2, &alpha, &beta);
	alpha = alpha * pi / 180;
	beta = beta * pi / 180;

	if (dcmp(beta - pi / 2) <= 0) {
		printf("%.7lf\n", Carea(alpha, l1 + l2) + Carea(beta, l2));
	} else {
		// l3 的角度
		f64 angel = pi - beta;	
		// 余弦
		f64 l3 = sqrt(l1 * l1 + l2 * l2 - 2.0 * l1 * l2 * cos(angel));
		// l2 与 l3 的夹角 >= 90
		f64 div;
		if (dcmp(l2 * l2 + l3 * l3 - l1 * l1) >= 0) {
			l3 = l1 * sin(angel);
			div = beta - pi / 2;
		} else {
			div = asin(l2 / l3 * sin(angel));
		}
		f64 S = l1 * l3 * sin(div) - Carea(div, l3);
		f64 S2 = 0;
		if (dcmp(div - 2 * alpha) == 1) {
			f64 l4 = l3 * sin(angel + div) / sin(2 * alpha + angel);
			S2 = l3 * l4 * sin(div - 2 * alpha) - Carea(div - 2 * alpha, l3);
		}
		printf("%.7lf\n", Carea(alpha, l1 + l2) + Carea(beta, l2) + S - S2);
	}
}

int main() {
	int T;
	scanf("%d", &T);

	while (T--) {
		solve();
	}
	return 0;
}