1. The problem states that the area of triangle ABD is 20. 2. The formula for the area of a triangle is $$\text{Area} = \frac{1}{2} \times \text{base} \times \text{height}$$. 3. To find any missing side or height, we need more information such as the length of the base or the height. 4. Since only the area is given, no further calculations can be done without additional data. 5. If you provide the base or height, I can help find the missing dimension using the area formula.