import sys
input = sys.stdin.readline

def calc(v,t,m):
    return v*t+v*v/(20*m)


eps=10**(-10)
T0=int(input())
for tests in range(T0):
    T,mu,L=map(float,input().split())

    OK=0
    NG=1<<60

    for tests in range(100):
        mid=(OK+NG)/2

        if calc(mid,T,mu)>L+eps:
            NG=mid
        else:
            OK=mid

    ANS=str(int(OK*360))

    while len(ANS)<3:
        ANS="0"+ANS

    print(ANS[:-2]+"."+ANS[-2:])