The question asks me to find the area of the triangle with the given vertices. (The area A of the triangle having u and v as adjacent sides is given by A=1/2 ||u x v||.)

Question

the vertices are:
(0,0,0) (1,2,3) (-3,0,0)

Answer 1

so, call the 3 points a,b,c
u=b-a = (1,2,3)
v=c-a = (-3,0,0)
now use the determinant to figure ||u x v||

Answer 2

Thank you!