Using the Box Method to Calculate the Area of a Parallelogram On a coordinate plane, parallelogram A B C D is shown. Point A is at (negative 3, negative 1), point B is at (7, 9), point C is at (8, negative 1), and point D is at (negative 2, negative 11). Create a rectangle around the parallelogram. The dimensions of this rectangle are . Find the area of the four right triangles surrounding the parallelogram. The total area of the triangles is square units. Subtract the triangle areas from the area of the rectangle to obtain the area of the parallelogram. The area of parallelogram ABCD is square units.