How does the area of a rectangle relate to it's length and width as one dimension increases and the other decreases?

Move the vertices of the rectangle so that they are located at the specified coordinates in the plane. Then calculate the area of the new rectangle. What happens as the length increases and the width decreases?
- Decrease the length of AB to 4 and increase AD to 18. What is the area of the new rectangle?
- Decrease the length of AB to 3 and increase AD to 24. What is the area of the new rectangle?
- Decrease the length of AB to 2 and increase AD to 36. What is the area of the new rectangle?
How would you describe the relationship of the length and width of all rectangles that have an area of 72?