The determinant formula:
The area of the triangle whose vertices are (x1,y1),(x2,y2), (x3,y3)
is given by this formula:



You can put the points in in any order as long as you take the absolute value
of the determinant:
(-1,3) (-2,0) (4,1)


Do you know how to expand (i.e., evaluate) a determinant? If not post again,
asking how. The value of the determinant is 17 so



Edwin