#include <bits/stdc++.h>
int main(void) {
  double c, x, y, a, b, t;
  scanf("%lf%lf%lf", &x, &y, &c);
  if ((x /= 2) < (y /= 2)) std::swap(x, y);
  if (0 > (b = y - x * (t = tan(c = acos(-1) / 360 * std::min(c, 180 - c)))))
    printf("%f\n", 4 * y * y / sin(2 * c));
  else
    a = x - y * t, a *= a * (t = tan(2 * c)),
    printf("%f\n", 4 * x * y - a - b * b * t);
  return 0;
}
