from math import*

def solve(B):

    α=b*sin((90-B)*pi/180)/sin(B*pi/180)

    s=α*b/2

    if α>a:s-=(α-a)*(b-b*a/α)/2

    return s>=x/a

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

ok=0

ng=90

while ng-ok>1e-7:

    mid=(ok+ng)/2

    if solve(mid):ok=mid

    else:ng=mid

print(ok)
from math import*

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

print((atan(2*(b/a-x/a**3)if x>a**2*b/2else a*b**2/(2*x))/pi*180))
from math import *


def solve(B):
    α = b * sin((90 - B) * pi / 180) / sin(B * pi / 180)
    s = α * b / 2
    if α > a:
        s -= (α - a) * (b - b * a / α) / 2
    return s >= x / a


a, b, x = list(map(int, input().split()))
ok = 0
ng = 90
while ng - ok > 1e-7:
    mid = (ok + ng) / 2
    if solve(mid):
        ok = mid
    else:
        ng = mid
print(ok)

from math import *

a, b, x = list(map(int, input().split()))
print(
    (
        atan(2 * (b / a - x / a**3) if x > a**2 * b / 2 else a * b**2 / (2 * x))
        / pi
        * 180
    )
)

- -def solve(B): -    α = b * sin((90 - B) * pi / 180) / sin(B * pi / 180) -    s = α * b / 2 -    if α > a: -        s -= (α - a) * (b - b * a / α) / 2 -    return s >= x / a - - -ok = 0 -ng = 90 -while ng - ok > 1e-7: -    mid = (ok + ng) / 2 -    if solve(mid): -        ok = mid -    else: -        ng = mid -print(ok) +print( +    ( +        atan(2 * (b / a - x / a**3) if x > a**2 * b / 2 else a * b**2 / (2 * x)) +        / pi +        * 180 +    ) +)