Answer:
cannot be determined
Step-by-step explanation:
In a parallelogram, the two opposite sides are equal. From the parallelogram ABCD given, it can be inferred that AB is parallel to CD and AD is parallel to BC i.e AB//CD and AD//BC.
Given AB = 18, side AD cannot be determined from the figure due to incomplete data given.
The data given can only be used to determine side CD since AB is equal to CD.
