Finding pi through computing area of a quarter circle -error---

[helloworld1123]

please help me . I have one day

question: Finding pi through computing area of a quarter circle



my code

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

int main()
{
  
    double sum,PI,h,x=0;            
    while (x<=2)
    {
    
    h=sqrt((2*2)-(x*x));    
    x=x+(2./20000.);
    sum=sum+h;
    }
    PI=sum*(1./10000.);
    cout << " Pi value is " <<setprecision(50)<<PI <<     
    system("pause");
    
    }

HOW can i fix it ?

The program cannot precisely find the value of pi.
result is

3.14169223

expect value: 3.1415926535