In quadrilateral ABCD, AD ∥ BC. What must the length of segment AD be for the quadrilateral to be a parallelogram? 8 units 16 units 31 units 62 units

it's 31

AD=BC

Step-by-step explanation:

For the Quadrilateral to be parallelogram it is compulsory that the one pair of opposite sides must be parallel as well as equal, one pair is enough since that will make the other also to follow the same property.

So on the basis of the above statement AD must have the length equal to BC since it is given that AD is parallel to BC.

Since the length of BC can be any of the options from given units and same length AD must have.