Answer:
never
Explanation:
Parallelograms have to have two parallel sides. For a shape to be a trapezoid it has to have only one pair of parallel sides, so a trapezoid is never a parallelogram.
A trapezoid has one pair of parallel sides, this is represented by the arrows on each side. But the rule of parallelograms states that for a shape to be a parallelogram all sides have to be parallel. Buty if you look at the properties of parallelograms you will see it states taht only one paor of sides are parrell. So becasie it does not have two pairs of parrell sides a trapazoid is not a parrallelogram.