import time

import math

a,b,x = list(map(int,input().split()))

x /= a

c = a*b/2

if x<c:

    l,r = 0,90

    for i in range(1000):

        mid = (l+r)/2

        S = b*b*math.tan(math.radians(mid))/2

        if S<=x: l = mid

        else: r = mid

    print((90-mid))

elif x==c:

    print((math.degrees(math.atan(a/b))))

else:

    l,r = 0,90

    for i in range(1000):

        mid = (l+r)/2

        S = a*b-a*a/math.tan(math.radians(mid))/2

        if S<=x: l = mid

        else: r = mid

    print((90-mid))
import math

a,b,x = list(map(int,input().split()))



x = x/a



if a*b/2>=x:

    S = (2*x)/(b*b)

    theta = math.atan(S)

    theta = math.degrees(theta)

    print((90-theta))

else:

    S = 2*(a*b-x)/(a*a)

    theta = math.atan(S)

    theta = math.degrees(theta)

    print(theta)
import time
import math

a, b, x = list(map(int, input().split()))
x /= a
c = a * b / 2
if x < c:
    l, r = 0, 90
    for i in range(1000):
        mid = (l + r) / 2
        S = b * b * math.tan(math.radians(mid)) / 2
        if S <= x:
            l = mid
        else:
            r = mid
    print((90 - mid))
elif x == c:
    print((math.degrees(math.atan(a / b))))
else:
    l, r = 0, 90
    for i in range(1000):
        mid = (l + r) / 2
        S = a * b - a * a / math.tan(math.radians(mid)) / 2
        if S <= x:
            l = mid
        else:
            r = mid
    print((90 - mid))

import math

a, b, x = list(map(int, input().split()))
x = x / a
if a * b / 2 >= x:
    S = (2 * x) / (b * b)
    theta = math.atan(S)
    theta = math.degrees(theta)
    print((90 - theta))
else:
    S = 2 * (a * b - x) / (a * a)
    theta = math.atan(S)
    theta = math.degrees(theta)
    print(theta)

-import time -x /= a -c = a * b / 2 -if x < c: -    l, r = 0, 90 -    for i in range(1000): -        mid = (l + r) / 2 -        S = b * b * math.tan(math.radians(mid)) / 2 -        if S <= x: -            l = mid -        else: -            r = mid -    print((90 - mid)) -elif x == c: -    print((math.degrees(math.atan(a / b)))) +x = x / a +if a * b / 2 >= x: +    S = (2 * x) / (b * b) +    theta = math.atan(S) +    theta = math.degrees(theta) +    print((90 - theta)) -    l, r = 0, 90 -    for i in range(1000): -        mid = (l + r) / 2 -        S = a * b - a * a / math.tan(math.radians(mid)) / 2 -        if S <= x: -            l = mid -        else: -            r = mid -    print((90 - mid)) +    S = 2 * (a * b - x) / (a * a) +    theta = math.atan(S) +    theta = math.degrees(theta) +    print(theta)