Math: Geometry -- What is the forumula for the Area of a Triangle?

The formula for figuring out the area of a triangle, using only the base and height is:

    Area = 1/2 * (base * height)

Why? Because, you can duplicate the triangle, rotate it 180 degrees, and that will create a parallelogram. The area of a parallelogram is the same as an area of a rectangle => base * height.
So, if 2 of the same triangles = the same as one rectangle of equal base & height, then 1 triangle is half the size calculation of that rectangle.