#include <bits/stdc++.h>
using namespace std;
double h, w, l;
double r;
void solve() {
  scanf("%lf%lf%lf", &w, &h, &l);
  if (w < h) swap(w, h);
  if (l >= 90) l = 180 - l;
  if (l == 90) {
    printf("%.8lf\n", h * h * 1.0);
    return;
  }
  if (l == 0) {
    printf("%.8lf\n", w * h * 1.0);
    return;
  }
  r = l * acos(-1.0) / 180.0;
  if (r < 2 * atan(h * 1.0 / w)) {
    double b = w / 2.0 - h / 2.0 * tan(r / 2);
    double a = h / 2.0 - w / 2.0 * tan(r / 2);
    double ans = w * h * 1.0;
    ans -= a * a * tan(r) + b * b * tan(r);
    printf("%.8lf\n", ans);
  } else {
    double ans = w * h * 1.0;
    double cnt = h * (w * 1.0 - h / sin(r));
    ans -= cnt;
    printf("%.8lf\n", ans);
  }
}
int main() { solve(); }
