program hungry;
uses math;
const
  pi=3.14159265357;
var
  i,k:longint;
  t:longint;
  l,s,d,j:real;
  area:real;
  tan,du:real;

begin
  assign(input,'hungry.in');
  reset(input);
  assign(output,'hungry.out');
  rewrite(output);

  readln(t);
  for k:=1 to t do
  begin
    readln(l,d,s);
    j:=sqrt(d*d+l*l/4);

    if s<=d then
    begin
      area:=pi*s*s;
    end
    else
    if s>=j then
    begin
      tan:=(l/2)/d;
      du:=arctan(tan);
      area:=pi*s*s*((pi-du)/pi);
      du:=pi/2-du;
      du:=pi-du;
      area:=area+pi*sqr(s-j)*(du/pi);
      area:=area+l*d/2;
    end
    else
    begin
      j:=sqrt(s*s-d*d);
      tan:=j/d;
      du:=arctan(tan);
      area:=pi*s*s*((pi-du)/pi);
      area:=area+j*d;
    end;

    writeln(area:0:2);
  end;

  close(input);
  close(output);
end.