/*--------------------------------------------------------------------*/ 
/*  This program computes the area of a sector of degrees d.         */ 
 
#include <iostream> 
using namespace std; 
 
const double PI = 3.141593; 
 
int main() 
{ 
   /*  Declare variables.  */ 
   double d, area, r, theta; 
 
   /*  Enter the radius of the sector.  */ 
   cout << "Enter the radius of the sector: "; 
   cin >> r; 

   /*  Enter the angle of the sector.  */
   cout << "Enter the angle in degrees of the sector: ";
   cin >> d;
 
   /* convert the degrees to radians  */
   theta = d * PI / 180.0;
 
   /*  Compute the area of the sector.  */ 
   area = r*r*theta/2.0; 
 
   /*  Print the value of the area.  */ 
   cout << "The area of a sector with radius " << r 
        << " and angle " << d << "  is " << area << endl; 
 
   /*  Exit program.  */ 
   return 0; 
} 
/*--------------------------------------------------------------------*/