#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
int main() {
double a, b, z, s;
cin >> a >> b >> z;
if ((1/(tan (z * M_PI / 180)) > a/sqrt(2)/b)&&(z != 0) && (z != 90)){
s = a * a / 2 / cos (z * M_PI / 180);
}
else if (z==0) {
s=0;
}
else if (z==90) {
s=a*b*sqrt(2);
}
else {
s=(a*sqrt(2)-b*1/(tan(z* M_PI / 180)))*b/sin(z* M_PI / 180);
}
cout << setprecision(3) << fixed << s;
return 0;
}
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