IV. decide whether the information given is enough to determine that a quadrilateral is a parallelogram 1. all four angles are congruent.
2. diagonals are perpendicular.
3. consecutive angles are supplementary.
4. diagonals are congruent and perpendicular.
5. both pairs of opposite sides are parallel.
6. two pairs of consecutive sides are congruent.
7. both pairs of opposite sides are congruent.
8. each diagonal bisects opposite angles. ​