#include <stdio.h>#include <math.h>#defineEPS1E-8doubleh, d, v;doubler;doublegetv(double s) {double_h;_h = r - s;return h * r * r * acos(_h / r) / 3.0 - _h * h * sqrt(r * r - _h * _h) * 2.0 / 3.0 + _h * _h * _h * h / r * log(( r + sqrt(r * r - _h * _h) ) / _h) / 3.0;}intmain() {intt;doublelft, rht, mid;scanf("%d", &t);while ( t-- ) {scanf("%lf%lf%lf", &h, &d, &v);r = d / 2.0;lft = 0.0;rht = r;while ( rht - lft > EPS ) {mid = ( lft + rht ) / 2.0;if ( getv(mid) < v ) lft = mid;else rht = mid;}printf("%.5lfn", d - ( lft + rht ) / 2.0);}return 0;}
