import
java.util.Scanner;
public
class
Main{
    
public
static
final
double
e = 
2.71828182845904523536028747135266249775724709369995957496696762772407663
;
    
public
static
void
main(String[] args){
        
Scanner in = 
new
Scanner(System.in);
        
int
T = in.nextInt();
        
while
(T-->
0
)
        
{
            
double
t=
1.0
,sum=
0
;
            
int
a = in.nextInt();
            
int
b = in.nextInt();
            
int
r = in.nextInt();
            
in.nextLine();
            
for
(
int
i=
0
;i<a;i++)
                
t*=e;
                
sum=b*t;
            
switch
(r)
            
{
                
case
1
:
                
System.out.printf(
"%.1f\n"
,sum);
                
break
;
                
case
2
:
                
System.out.printf(
"%.2f\n"
,sum);
                
break
;
                
case
3
:
                
System.out.printf(
"%.3f\n"
,sum);
                
break
;
                
case
4
:
                
System.out.printf(
"%.4f\n"
,sum);
                
break
;
                
case
5
:
                
System.out.printf(
"%.5f\n"
,sum);
                
break
;
            
}
         
}
        
in.close();
      
}
}