Problem.B

#include <stdio.h>
int main(){
    double a, b, c, p;
    int n;
    scanf("%d", &n);
    while(n--){
        scanf("%lf%lf%lf", &a, &b, &c);
        p = (a + b + c) / 2;
        printf("%.1f\n", p * (p - a) * (p - b) * (p - c));
    }
    return 0;
}