Question

If a(-1,3) b(1,-1) and c(5,1) are the vertices of a trangle

Answer 1

A(-1,3) B(1,-1) c(5,1)

=1/2(x1(y2-y3) x2(y3-y1) x3 (y1-y2))

=1/2(-1(-1-1) +1(1+1) 5(3+1))

=1/2(-1(-2) +1(2) +5 (4))

=1/2(2+2+24)

=1/2(24)

=12