2009-03-01 09:31:13來源不明

95高市資訊學科能力競賽 繩子上吃草的牛

橢圓面績!

/*************************************************************/

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
main()
{
 double pi=2*acos(0.0),x,y;
 while(scanf("%lf %lf",&x,&y)==2)
  {
   double longlong,shortshort,ans;
   longlong=sqrt((y/2)*(y/2)-(x/2)*(x/2));  
   shortshort=x/2+(y-x)/2;
   ans=shortshort*longlong*pi;
   printf("%.3lf\n",ans);
  }
 return 0;
}