#include <stdio.h>
int main()
{
    float x1,y1,x2,y2,x3,y3,u1x,u1y,u2x,u2y,areaTriangle;

    printf("\nEnter the components of the first vector.\n\n");
    printf("x1 = ");
    scanf("%f", &x1);
    printf("\ny1 = ");
    scanf("%f", &y1);

    printf("\nEnter the components of the second vector.\n\n");
    printf("x2 = ");
    scanf("%f", &x2);
    printf("\ny2 = ");
    scanf("%f", &y2);

    printf("\nEnter the components of the third vector.\n\n");
    printf("x3 = ");
    scanf("%f", &x3);
    printf("\ny3 = ");
    scanf("%f", &y3);

    u1x = x2-x3;
    u1y = y2-y3;
    u2x = x1-x3;
    u2y = y1-y3;

    areaTriangle = sqrt(pow((u1x*u2y-u2x*u1y)/2,2));


    printf("\nThe area of this triangle is %f.\n\n", areaTriangle);

    return 0;

}