#if __INCLUDE_LEVEL__ == 0

#include __BASE_FILE__

namespace {

using kactl::ldbl;
using kactl::P;

double F(double x, double b) {
  if (b == 0) {
    x = std::abs(x);
    return x * x * x / 6;
  }
  double ret = x * std::log(std::sqrt(x * x + b * b) + x) - std::sqrt(x * x + b * b);
  ret *= b * b;
  ret += std::pow(x * x + b * b, 1.5) / 3;
  ret /= 2;
  return ret;
}

double solve(double a, double b) { return F(-a, b) - F(1 - a, b); }

double solve(P B) {
  if (B.y < 0) {
    B.y = -B.y;
    return -solve(B);
  }

  if (B.x != 1) {
    return solve(B / B.x) * B.x * B.x * B.x;
  }

  const double b = B.y;
  const double c = B.dist();

  return (b * c + std::log(b + c)) / 6;
}

double solve(P A, P B) {
  {
    const double t = std::numbers::pi / 2 - (B - A).angle();
    A = A.rotate(t);
    B = B.rotate(t);
  }
  return solve(B) - solve(A);
}

ldbl solve(P p1, P p2, P p3, P p4) {
  if ((p2 - p1).cross(p4 - p3) == 0) {
    p3 = kactl::linearTransformation(p1, p2, P(0, 0), P(1, 0), p3);
    p4 = kactl::linearTransformation(p1, p2, P(0, 0), P(1, 0), p4);
    assert(p3.y == p4.y);
    if (p3.y < 0) {
      p3.y = -p3.y;
      p4.y = -p4.y;
    }
    if (p4.x < p3.x) {
      std::swap(p3, p4);
    }
    double ans = solve(p4.x, p3.y) - solve(p3.x, p3.y);
    ans /= p4.x - p3.x;
    ans *= (p2 - p1).dist();
    return ans;

  } else {
    auto hull = kactl::convexHull({p3 - p1, p4 - p1, p3 - p2, p4 - p2});
    assert(len(hull) == 4);
    hull.push_back(hull[0]);

    double ans = 0;
    double area = 0;
    for (const int i : rep(4)) {
      const double cross = hull[i].cross(hull[i + 1]);
      if (0 < cross) {
        ans += solve(hull[i], hull[i + 1]);
      } else if (cross < 0) {
        ans -= solve(hull[i + 1], hull[i]);
      }
      area += cross;
    }
    area /= 2;
    ans /= area;
    return ans;
  }
}

void solve() {
  P p1, p2;
  scan(p1.x, p1.y, p2.x, p2.y);
  P p3, p4;
  scan(p3.x, p3.y, p4.x, p4.y);

  std::cout << std::setprecision(DBL_DIG);
  print(solve(p1, p2, p3, p4));
}

}  // namespace

int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);

  int t;
  scan(t);
  while (t--) {
    solve();
  }
}

#else  // __INCLUDE_LEVEL__

#include <bits/stdc++.h>

// https://github.com/kth-competitive-programming/kactl
namespace kactl {

using namespace std;

#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

using ldbl = long double;
#define double ldbl

template <class T>
int sgn(T x) {
  return (x > 0) - (x < 0);
}
template <class T>
struct Point {
  typedef Point P;
  T x, y;
  explicit Point(T x = 0, T y = 0) : x(x), y(y) {}
  bool operator<(P p) const { return tie(x, y) < tie(p.x, p.y); }
  bool operator==(P p) const { return tie(x, y) == tie(p.x, p.y); }
  P operator+(P p) const { return P(x + p.x, y + p.y); }
  P operator-(P p) const { return P(x - p.x, y - p.y); }
  P operator*(T d) const { return P(x * d, y * d); }
  P operator/(T d) const { return P(x / d, y / d); }
  T dot(P p) const { return x * p.x + y * p.y; }
  T cross(P p) const { return x * p.y - y * p.x; }
  T cross(P a, P b) const { return (a - *this).cross(b - *this); }
  T dist2() const { return x * x + y * y; }
  double dist() const { return sqrt((double)dist2()); }
  double angle() const { return atan2(y, x); }
  P unit() const { return *this / dist(); }
  P perp() const { return P(-y, x); }
  P normal() const { return perp().unit(); }
  P rotate(double a) const { return P(x * cos(a) - y * sin(a), x * sin(a) + y * cos(a)); }
  friend ostream& operator<<(ostream& os, P p) { return os << "(" << p.x << "," << p.y << ")"; }
};

typedef Point<double> P;
vector<P> convexHull(vector<P> pts) {
  if (sz(pts) <= 1) return pts;
  sort(all(pts));
  vector<P> h(sz(pts) + 1);
  int s = 0, t = 0;
  for (int it = 2; it--; s = --t, reverse(all(pts)))
    for (P p : pts) {
      while (t >= s + 2 && h[t - 2].cross(h[t - 1], p) <= 0) t--;
      h[t++] = p;
    }
  return {h.begin(), h.begin() + t - (t == 2 && h[0] == h[1])};
}

typedef Point<double> P;
P linearTransformation(const P& p0, const P& p1, const P& q0, const P& q1, const P& r) {
  P dp = p1 - p0, dq = q1 - q0, num(dp.cross(dq), dp.dot(dq));
  return q0 + P((r - p0).cross(num), (r - p0).dot(num)) / dp.dist2();
}

#undef sz
#undef all

}  // namespace kactl

template <class T, class U = T>
bool chmin(T& x, U&& y) {
  return y < x && (x = std::forward<U>(y), true);
}

template <class T, class U = T>
bool chmax(T& x, U&& y) {
  return x < y && (x = std::forward<U>(y), true);
}

template <class T>
concept Range = std::ranges::range<T> && !std::convertible_to<T, std::string_view>;

template <class T>
concept TupleLike = std::__is_tuple_like<T>::value && !Range<T>;

namespace std {

istream& operator>>(istream& is, Range auto&& r) {
  for (auto&& e : r) {
    is >> e;
  }
  return is;
}

istream& operator>>(istream& is, TupleLike auto&& t) {
  return apply([&](auto&... xs) -> istream& { return (is >> ... >> xs); }, t);
}

ostream& operator<<(ostream& os, Range auto&& r) {
  string_view sep = "";
  for (auto&& e : r) {
    os << exchange(sep, " ") << e;
  }
  return os;
}

ostream& operator<<(ostream& os, TupleLike auto&& t) {
  const auto f = [&](auto&... xs) -> ostream& {
    [[maybe_unused]] string_view sep = "";
    ((os << exchange(sep, " ") << xs), ...);
    return os;
  };
  return apply(f, t);
}

#define DEF_INC_OR_DEC(op) \
  auto& operator op(Range auto&& r) { \
    for (auto&& e : r) { \
      op e; \
    } \
    return r; \
  } \
  auto& operator op(TupleLike auto&& t) { \
    apply([](auto&... xs) { (op xs, ...); }, t); \
    return t; \
  }

DEF_INC_OR_DEC(++)
DEF_INC_OR_DEC(--)

#undef DEF_INC_OR_DEC

}  // namespace std

void scan(auto&&... xs) { std::cin >> std::tie(xs...); }
void print(auto&&... xs) { std::cout << std::tie(xs...) << '\n'; }

#define FWD(...) static_cast<decltype(__VA_ARGS__)&&>(__VA_ARGS__)

template <class F>
class fix {
 public:
  explicit fix(F f) : f_(std::move(f)) {}

  decltype(auto) operator()(auto&&... xs) const { return f_(std::ref(*this), FWD(xs)...); }

 private:
  F f_;
};

template <class T>
concept LambdaExpr = std::is_placeholder_v<std::remove_cvref_t<T>> != 0 ||
                     std::is_bind_expression_v<std::remove_cvref_t<T>>;

auto operator++(LambdaExpr auto&& x, int) {
  return std::bind([](auto&& x) -> decltype(auto) { return FWD(x)++; }, FWD(x));
}

auto operator--(LambdaExpr auto&& x, int) {
  return std::bind([](auto&& x) -> decltype(auto) { return FWD(x)--; }, FWD(x));
}

#define DEF_UNARY_OP(op) \
  auto operator op(LambdaExpr auto&& x) { \
    return std::bind([](auto&& x) -> decltype(auto) { return op FWD(x); }, FWD(x)); \
  }

DEF_UNARY_OP(++)
DEF_UNARY_OP(--)
DEF_UNARY_OP(+)
DEF_UNARY_OP(-)
DEF_UNARY_OP(~)
DEF_UNARY_OP(!)
DEF_UNARY_OP(*)
DEF_UNARY_OP(&)

#undef DEF_UNARY_OP

#define DEF_BINARY_OP(op) \
  template <class T1, class T2> \
    requires LambdaExpr<T1> || LambdaExpr<T2> \
  auto operator op(T1&& x, T2&& y) { \
    return std::bind([](auto&& x, auto&& y) -> decltype(auto) { return FWD(x) op FWD(y); }, \
                     FWD(x), FWD(y)); \
  }

DEF_BINARY_OP(+=)
DEF_BINARY_OP(-=)
DEF_BINARY_OP(*=)
DEF_BINARY_OP(/=)
DEF_BINARY_OP(%=)
DEF_BINARY_OP(^=)
DEF_BINARY_OP(&=)
DEF_BINARY_OP(|=)
DEF_BINARY_OP(<<=)
DEF_BINARY_OP(>>=)
DEF_BINARY_OP(+)
DEF_BINARY_OP(-)
DEF_BINARY_OP(*)
DEF_BINARY_OP(/)
DEF_BINARY_OP(%)
DEF_BINARY_OP(^)
DEF_BINARY_OP(&)
DEF_BINARY_OP(|)
DEF_BINARY_OP(<<)
DEF_BINARY_OP(>>)
DEF_BINARY_OP(==)
DEF_BINARY_OP(!=)
DEF_BINARY_OP(<)
DEF_BINARY_OP(>)
DEF_BINARY_OP(<=)
DEF_BINARY_OP(>=)
DEF_BINARY_OP(&&)
DEF_BINARY_OP(||)

#undef DEF_BINARY_OP

template <class T1, class T2>
  requires LambdaExpr<T1> || LambdaExpr<T2>
auto at(T1&& x, T2&& y) {
  return std::bind([](auto&& x, auto&& y) -> decltype(auto) { return FWD(x)[FWD(y)]; }, FWD(x),
                   FWD(y));
}

template <int I>
auto get(LambdaExpr auto&& x) {
  return std::bind([](auto&& x) -> decltype(auto) { return std::get<I>(FWD(x)); }, FWD(x));
}

inline auto rep(int l, int r) { return std::views::iota(std::min(l, r), r); }
inline auto rep(int n) { return rep(0, n); }
inline auto rep1(int l, int r) { return rep(l, r + 1); }
inline auto rep1(int n) { return rep(1, n + 1); }

#define len(...) static_cast<int>(ranges::distance(__VA_ARGS__))

using namespace std::literals;
using namespace std::placeholders;

namespace ranges = std::ranges;
namespace views = std::views;

using i64 = std::int64_t;

#endif  // __INCLUDE_LEVEL__