finding the area of a triangle

LINK:www.pballew.net/detrmnt.doc

for example if your given a problem about finding the area of a triangle with this given information A(2,1);B(5,6);C(9,-1).If you don't know
the determinant you will have to find the lenght of AB AC and BC then find the area we get 20.5.But there is an easy way to find the area is by the method of
determinant we put the x values in the first column then the y values in the second column and in the third column we put 1.Then we do the method
of determinant and we get -41.So 41 is half 20.5.And we can get + if we interchange the rows.

first method:
AB=root 34
AC=root 65
BC=root 53
if we add them all we get 20.5

method of determinant
det{2 1 1}
{5 6 1}
{9 -1 1}
= -41
Finally if we want to find the area of a triangle all we have to do is find the absolute value of the determinant over 2, it is easy, simple
and we can save time.

Sami Nassif