import java.io.InputStream;
import java.io.PrintStream;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	InputStream in = System.in;
	PrintStream out = System.out;

	// theta(rad)傾けた時の最大容量
	double f(double theta) {
		if(b*Math.sin(Math.PI/2-theta) > a*Math.sin(theta)) {
			return a*a*b-(a*a*a*Math.tan(theta)/2);
		}else {
			return b*b*Math.tan(Math.PI/2-theta)/2 * a;
		}
	}
	
	int a,b;
	
	public void _main(String[] args) {
		Scanner sc = new Scanner(in);

		a = sc.nextInt();
		b = sc.nextInt();
		int x = sc.nextInt();

		sc.close();
		
		double eps = 0.00000001;
		

		double l = 0;
		double r = Math.PI / 2;
		
		while(true) {
			if(r-l < eps) {
				break;
			}
			
			double m = (r-l)/2 + l;
//			System.err.println(Math.toDegrees(l) + "\t" + Math.toDegrees(r) + "\t"  + Math.toDegrees(m) + "\t" + f(m));
			if( x < f(m)) {
				l = m;
			}else {
				r = m;
			}
			
		}
		
		out.println(Math.toDegrees(l));
		

	}

	public static void main(String[] args) {
		new Main()._main(args);
	}

	@SuppressWarnings("unused")
	private String join(String delimiter, int[] a) {
		StringBuilder sb = new StringBuilder();

		for (int i = 0; i < a.length; i++) {
			sb.append(a[i]);
			sb.append(delimiter);
		}
		return sb.substring(0, Math.max(sb.length() - delimiter.length(), 0));
	}

	@SuppressWarnings("unused")
	private String join(String delimiter, long[] a) {
		StringBuilder sb = new StringBuilder();

		for (int i = 0; i < a.length; i++) {
			sb.append(a[i]);
			sb.append(delimiter);
		}
		return sb.substring(0, Math.max(sb.length() - delimiter.length(), 0));
	}

	@SuppressWarnings("unused")
	private int max(int[] arr) {
		if(arr == null || arr.length == 0) {
			throw new IllegalArgumentException(Arrays.toString(arr));
		}

		int candidate = arr[0];
		for(int i=1;i<arr.length;i++) {
			candidate = candidate > arr[i] ? candidate : arr[i];
		}
		return candidate;
	}

	@SuppressWarnings("unused")
	private long max(long[] arr) {
		if(arr == null || arr.length == 0) {
			throw new IllegalArgumentException(Arrays.toString(arr));
		}

		long candidate = arr[0];
		for(int i=1;i<arr.length;i++) {
			candidate = candidate > arr[i] ? candidate : arr[i];
		}
		return candidate;
	}

	@SuppressWarnings("unused")
	private int min(int[] arr) {
		if(arr == null || arr.length == 0) {
			throw new IllegalArgumentException(Arrays.toString(arr));
		}

		int candidate = arr[0];
		for(int i=1;i<arr.length;i++) {
			candidate = candidate < arr[i] ? candidate : arr[i];
		}
		return candidate;
	}

	@SuppressWarnings("unused")
	private long min(long[] arr) {
		if(arr == null || arr.length == 0) {
			throw new IllegalArgumentException(Arrays.toString(arr));
		}

		long candidate = arr[0];
		for(int i=1;i<arr.length;i++) {
			candidate = candidate < arr[i] ? candidate : arr[i];
		}
		return candidate;
	}

	@SuppressWarnings("unused")
	private int[] nextIntArray(Scanner sc, int n) {
		int[] result = new int[n];
		for (int i = 0; i < n; i++) {
			result[i] = sc.nextInt();
		}
		return result;
	}

	@SuppressWarnings("unused")
	private long[] nextLongArray(Scanner sc, int n) {
		long[] result = new long[n];
		for (int i = 0; i < n; i++) {
			result[i] = sc.nextLong();
		}
		return result;
	}

	@SuppressWarnings("unused")
	private int[] nextIntArray1origin(Scanner sc, int n) {
		int[] result = new int[n + 1];
		for (int i = 1; i <= n; i++) {
			result[i] = sc.nextInt();
		}
		return result;
	}
}


Measured memory_bytes: 23764