trig functions returning incorrect values

I've been trying to write a program that uses the trig functions in cmath, sin() and cos() in particular. I understand that these functions use radians so I added * pi / 180 however the program still displays incorrect numbers. Here is some code.

    #include<iostream>
    #include<cmath>
    using namespace std;

    const double pi = 3.1415926;

    int main()
    {
        int x = 0;
        double d;
        for(int forl=0;forl < 10;forl++)
        {
           d = sin(50 / pi * 180);
           cout << d << endl;
           x += 5;
        }
        cin >> x;
        return 0;
    }

WHy does this code display incorrect numbers?