const pi=3.1415926535897932384626;
var t,n,i:longint;
    r:real;
begin
  readln(t);
  for i:=1 to t do begin
    readln(r,n);
    writeln('Scenario #',i,':');
    if n<=2 then writeln(r/n:0:3)
    else writeln(r/(sin((pi-2*pi/n)/2)/sin(2*pi/n)+0.5)/2:0:3);
    writeln;
  end;
end.