Final answer:
Line AC and Line BD are perpendicular to each other.
Step-by-step explanation:
In this scenario, we have Line AB parallel to Line CD, and both Line AC and Line BD are perpendicular to Line AB and Line CD. Since two perpendicular lines intersect at a 90-degree angle, we can say that Line AC and Line BD are also perpendicular to each other. This means that Line AC forms a 90-degree angle with Line BD.