Hello, rtblue!

As a matter of fact, therea neat formula for this problem.is

If you understand determinants, you'll like this . . .What is the area of the triangle whose vertices are (0, 0), (14, 6), and (12, 9)?

The area of the triangle with vertices: . is:

. . . . .

For your three vertices:

. .

. . . .

Note: The "determinant bars" also representabsolute value.

. . . . .The determinent can turn out to be negative.

Edit: correct a silly oversight . . .

.