Area of a triangle

#include <stdio.h>
#include <math.h>

typedef struct {
     float x;
     float y;
     } point;

typedef struct {
     point ver1;
     point ver2;
     point ver3;
     } triangle;

float area(triangle T) {
     return(fabs((T.ver2.x - T.ver1.x)*(T.ver3.y-T.ver1.y) -
     (T.ver2.y - T.ver1.y)*(T.ver3.x-T.ver1.x))/2);
}

int main() {

triangle T;
float a;

printf("The first point is: ");
scanf("%f %f",&T.ver1.x,&T.ver1.y);

printf("The second point is: ");
scanf("%f %f",&T.ver2.x,&T.ver2.y);

printf("The third point is: ");
scanf("%f %f",&T.ver3.x,&T.ver3.y);

a = area(T);
printf("The area of the triangle is %f.\n",a);
}

Volume of a tetrahedron

#include <stdio.h>
#include <math.h>

typedef struct {
        float x;
        float y;
        float z;
} point;

typedef struct {
        point ver1;
        point ver2;
        point ver3;
        point ver4;
} tetrahedron;


point Diff(point a, point b) {
        point c;

        c.x = a.x - b.x;
        c.y = a.y - b.y;
        c.z = a.z - b.z;

        return(c);
}


point Cross(point a, point b) {
        point c;

        c.x = a.y*b.z - a.z*b.y;
        c.y = a.z*b.x - a.x*b.z;
        c.z = a.x*b.y - a.y*b.x;

        return(c);
}

float Dot(point a, point b) {
        return(a.x*b.x + a.y*b.y + a.z*b.z);
}

float Volume(tetrahedron t) {
        point a, b, c;

        a = Diff(t.ver3,t.ver1);
        b = Diff(t.ver2,t.ver1);
        c = Diff(t.ver4,t.ver1);

        return(fabs(Dot(c,Cross(a,b)))/6);
}

int main(){
        tetrahedron T;
        float vol;

printf("The coordinates of the first point are: ");
scanf("%f %f %f", &T.ver1.x, &T.ver1.y, &T.ver1.z);

printf("The coordinates of the second point are: ");
scanf("%f %f %f", &T.ver2.x, &T.ver2.y, &T.ver2.z);

printf("The coordinates of the third point are: ");
scanf("%f %f %f", &T.ver3.x, &T.ver3.y, &T.ver3.z);

printf("The coordinates of the fourth point are: ");
scanf("%f %f %f", &T.ver4.x, &T.ver4.y, &T.ver4.z);

vol = Volume(T);

printf("The volume of the tetrahedron T is equal to %f\n", vol);

}