#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cassert>
#include <iostream>
#include <string>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <sstream>
#include <bitset>

using namespace std;
typedef long long ll;

int main() {
    std::ios::sync_with_stdio(0); cin.tie(0);


    ll ans=0;
    ll anss =0;
    ll count=0;
    ll i,j;
  
    long double x;
    vector<ll> aa;

    ll Q,N;
    long double a, b;
    string S;
    cin >> a >> b >> x;
    ll flag=0;
    ll t1=0;
    ll t2=0;
  	

    if(x>=a*a*b/2){
      
     	long double dans = (atan2((2*b-2*x/a/a),a))*180/M_PI;
        cout <<std::setprecision(12)<< dans  << endl;
        return 0;
      
    }else{
     
     	long double dans =(atan2(b,(2*x/a/b)))*180/M_PI ;
        cout <<std::setprecision(12)<< dans << endl;
      	return 0;
      
    }
   
    return 0;
}