#include <stdio.h>
#include <math.h>
int main(int argc, char * argv[])
{
double a,b,c,s,area;
a=3.67;
b=5.43;
c=6.21;
s=(a+b+c)/2;
area=sqrt(s*(s-a)*(s-b)*(s-c));
printf("a=%f\tb=%f\tc=%f\n",a,b,c);
printf("area =%f\n",area);
return 0;
}