#include#includevoid main(){float a,b,c,s,area;printf("please input a,b,c\n");scanf("%f%f%f",&a,&b,&c);if(a+b>c&&b+c>a&&c+a>b){s=(a+b+c)/2;area=(float)sqrt(s*(s-a)*(s-b)*(s-c));printf("area=%f\n",area...