00:01
We are given the vertices of a triangle, and we're asked to find the area of this triangle.
00:08
The vertices are 2 -40, negative 2, negative 4 -0, and 0 -0 -0.
00:26
To find the area of this triangle, we'll need to find the area of the parallelogram formed by mirroring this triangle across one of its sides.
00:34
To find the area of this parallelogram, we need to find the cross -product of the two vectors which span the parallelogram, and these are the same.
00:44
These two vectors, one of them, vector u is the vector from the first point to the second point, and the other one, vector v, is the vector from the first point to the third point.
00:57
So in component form, u is using terminal point minus initial point, negative 2 minus 2, 2, negative 4 minus 4, 0 minus 0, which is equal to negative 4, negative 8, 0.
01:16
And component form, v is 0 minus 2, 0 minus 4, 4 minus 0, which is equal to negative 2, negative 4, 4, 4...