#微分法，可以用来求不好算积分的曲线，精度由dy控制
import math
while True:
    try:
        T=int(input())
        for _ in range(T):
            A,B,C=list(map(int,input().split()))
            
            a=B*B
            b=2*B*C-2*A
            c=C*C
            dt=b*b-4*a*c

            if dt<=0:
                print(0)
                
            else :
                x1=(-b-math.sqrt(dt))/(2*a)
                x2=(-b+math.sqrt(dt))/(2*a)
                y1=B*x1+C
                y2=B*x2+C
                
                # 微分法
                dy=0.01
                # y_list = [i*dy for i in range(math.floor(y1/dy),math.ceil(y2/dy))]
                def y_generator(y1,y2,dy):
                    for i in range(math.floor(y1/dy),math.ceil(y2/dy)):
                        yield i*dy 
                y_list = y_generator(y1,y2,dy)
                
                ans=0
                for y in y_list:
                    d = abs(((y-C)/B)-(y*y)/(2*A))
                    ans+=d
                print(ans*dy)
            
    except: break
        

from scipy.integrate import quad
from sympy import *
from sympy.core.add import add

def area_compute():
    t = int(input('输入次数t:'))
    while t:
        t -= 1
        A,B,C = map(float,(input('输入三个数:').split()))
        
        def func(x):
            y1 = x ** 2 / 2 / A
            y2 = (x - C) / B
            return y2 - y1

        x = symbols('x')
        expre = x ** 2 / 2 / A - (x - C) / B
        res = solve(expre, x)  # 计算两线交点
        if isinstance(res[0], Add):  # 解为复数
            print(0)
            continue
        elif len(res)==1:   # 只有一个解
            print(0)
            continue
        else:
            fA,err = quad(func,res[0],res[1])   # 用定积分求包含部分的面积
            print(fA)

area_compute()