I need to find the area of of a triangle with the given vertices:
A(1,1) B(2,2) C(3,-3)
I found the lengths of these, and used 1/2llallllbllllallllbll.
Which I got to result in the area equals 12. Is this correct?
If I do it using area= P1P2P3= 1/2
I end up with:
Which can be row reduced to:
I then use cofactor expansion:
When I find the determinant of the cofactor i get:
This gives me 3 as an answer...
Which way is right? Or are both wrong?