数学问题，二分法即可
记得精度问题
//====================================================================||
// ||
// ||
// 作者 : GCA ||
// 6AE7EE02212D47DAD26C32C0FE829006 ||
//====================================================================||
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <climits>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <cctype>
#include <utility>
using namespace std;
#ifdef ONLINE\_JUDGE
#define ll "%lld"
#else
#define ll "%I64d"
#endif
typedef unsigned int uint;
typedef long long int Int;
#define Set(a,s) memset(a,s,sizeof(a))
#define Write(w) freopen(w,"w",stdout)
#define Read(r) freopen(r,"r",stdin)
#define Pln() printf("\\n")
#define I\_de(x,n)for(int i=0;i<n;i++)printf("%d ",x\[i\]);Pln()
#define De(x)printf(#x"%d\\n",x)
#define For(i,x)for(int i=0;i<x;i++)
#define CON(x,y) x##y
#define Pmz(dp,nx,ny)for(int hty=0;hty<ny;hty++){for(int htx=0;htx<nx;htx++){\\
printf("%d ",dp\[htx\]\[hty\]);}Pln();}
#define M 55
#define PII pair<int,int\>
#define PB push\_back
#define oo INT\_MAX
#define Set\_oo 0x3f
#define Is\_debug true
#define debug(...) if(Is\_debug)printf("DEBUG: "),printf(\_\_VA\_ARGS\_\_)
#define FOR(it,c) for(\_\_typeof((c).begin()) it=(c).begin();it!=(c).end();it++)
#define eps 1e-9
bool xdy(double x,double y){return x>y+eps;}
bool xddy(double x,double y){return x>y-eps;}
bool xcy(double x,double y){return x<y-eps;}
bool xcdy(double x,double y){return x<y+eps;}
int min3(int x,int y,int z){
int tmp=min(x,y);
return min(tmp,z);
}
int max3(int x,int y,int z){
int tmp=max(x,y);
return max(tmp,z);
}
double r,p;
double pi=3.14159;
inline double sq(double a){return a\*a;}
double cal(double cr){
double da=acos(1-sq(cr)/(2\*sq(r)));
double ca=acos(cr/(2\*r));
double ans=sq(r)\*(da-sin(da))+sq(cr)\*ca;
// debug("%lf %lf %lf %lf %lf\\n",da,ca,squ,daa,caa);
return ans;
}
int main() {
ios\_base::sync\_with\_stdio(0);
int test;
scanf("%d",&test);
while(test--){
scanf("%lf%lf",&r,&p);
double rr=2\*r;
double l=0;
double a=r\*r\*pi\*p;
while(xdy(rr,l)){
double m=(rr+l)/2;
if(cal(m)>a)rr=m;
else l=m;
}
printf("R = %.0f, P = %.2f, Rope = %.2f\\n",r,p,rr);
if(test)Pln();
}
}